Could gastrointestinal disorders differ in two close but divergent social environments?

  • Ewa Grodzinsky1,

    Affiliated with

    • Claes Hallert2,

      Affiliated with

      • Tomas Faresjö3,

        Affiliated with

        • Elisabet Bergfors1 and

          Affiliated with

          • Åshild Olsen Faresjö3Email author

            Affiliated with

            International Journal of Health Geographics201211:5

            DOI: 10.1186/1476-072X-11-5

            Received: 15 November 2011

            Accepted: 6 February 2012

            Published: 6 February 2012

            Abstract

            Background

            Many public health problems in modern society affect the gastrointestinal area. Knowledge of the disease occurrence in populations is better understood if viewed in a psychosocial context including indicators of the social environment where people spend their lives. The general aim of this study was to estimate the occurrence in the population and between sexes of common gastrointestinal conditions in two neighborhood cities representing two different social environments defined as a "white-collar" and a "blue-collar" city.

            Methods

            We conducted a retrospective register study using data of diagnosed gastrointestinal disorders (cumulative incidence rates) derived from an administrative health care register based on medical records assigned by the physicians at hospitals and primary care.

            Results

            Functional gastrointestinal diseases and peptic ulcers were more frequent in the white-collar city, while diagnoses in the gallbladder area were significantly more frequent in the blue-collar city. Functional dyspepsia, irritable bowel syndrome, and unspecified functional bowel diseases, and celiac disease, were more frequent among women while esophageal reflux, peptic ulcers, gastric and rectal cancers were more frequent among men regardless of social environment.

            Conclusions

            Knowledge of the occurrence of gastrointestinal problems in populations is better understood if viewed in a context were the social environment is included. Indicators of the social environment should therefore also be considered in future studies of the occurrence of gastrointestinal problems.

            Keywords

            Social environment General population Gastrointestinal disorders Sex Public health

            Background

            Many public health problems in modern society affect the gastrointestinal area. Knowledge of the disease occurrence in populations is better understood if viewed in a psychosocial context including indicators of the social environment where people spend their lives. The etiology of functional gastrointestinal diseases (FGD) such as irritable bowel syndrome (IBS), functional dyspepsia (FD) and gastroesophageal reflux (GERD) is complex and in many ways still unclear and there is still a lack of understanding of the pathology [1, 2]. The dysfunctions that lead to or aggravate FGD are a combination of biological, psychological and psychosocial factors [3]. These multiple sets of factors are likely to interact in the pathogenesis and clinical manifestations of the disorders. This multi-factorial pattern is often evident in other gastrointestinal disorders and in many other public health diseases in a complex contemporary society. Several attempts have been made to create bio-psycho-social models to help bring some order to factors and to explain the interaction of environmental, cultural, social, psychological and biological factors [46].

            Knowledge of the disease prevalence rates is crucial for describing the population burden of diseases and assessing the associated health care utilization and health care cost [7]. Available sources for this purpose include health surveys, screening investigations, and register studies [8]. Previous studies of functional gastrointestinal disorders such as IBS have shown the value of using administrative health care registers [9, 10]. The General Practice Research Database (GPRD) in United Kingdom (UK) had also been used in different studies of several diseases such as GERD and chronic obstructive pulmonary disease [11, 12] as well as detection of colorectal tumor and inflammatory bowel disease (IBD) among patients with IBS [13, 14].

            The role and importance of social and physical environments for health, the effect of residence and the question of whether we should focus on context rather than people is still an open question in health sciences [1517]. A general conclusion as regards this issue is that who you are, but also how and where you live your life are both of importance for health outcomes [18]. In order to address this issue, we conducted a study focusing on the population in two equally sized Swedish cities, so called the "Twin cities". These two cities are geographically close and part of the same public health care system managed by Östergötland County Council. However, the social and cultural history and current social structure of these two cities differ; one city could be described as a "blue-collar" city and the other as a "white-collar" city. Thereby, these twin cities are neighborhood cities but represent two different social environments.

            Study aims

            The general aim of this study was to estimate the occurrence in the population and between sexes of common gastrointestinal conditions in different social environments defined as a "white-collar" and a "blue-collar" city.

            Methods

            The study population in the twin cities

            We focused on the population in two equally sized cities (the twin cities) located 40 km (25 miles) apart in the same county in the south-east of Sweden, namely, the city of Norrköping (N) and the city of Linköping (L). The two cities are quite equal in size and there are neither any age nor sex distribution differences between them [19]. Both cities are managed by the same health care organization; the county council is responsible for all public-funded health care in the two cities. However, the past and even the current socio-economic structures in the two cities are different, see Table 1. One of the cities (L) is dominated by high-tech industries and higher education institutions, and may be regarded as a white-collar city, while the other (N) has a long industrial history and could be viewed upon as a blue-collar city. Although the cities today have an extrinsic resemblance in terms of physical environment and climate, public health is remarkably different in these two cities [19]. This is manifested in a number of public health indicators including life expectancy, prevalence of ischemic heart disease, sick leave, and lifestyle factors consistently in favour of the "white-collar" city [19, 20].
            Table 1

            Indicators of the social environments in the "white-collar" and "blue-collar" twin city

              

            White-collar twin city

            Blue-collar twin city

            Total number of inhabitants (2009)

             

            144 690

            129 254

            Life expectancy at birth

            Women

            82.6

            81.8

             

            Men

            79.5

            77.9

            Inhabitants born outside Europe (%)

             

            9.6

            11.0

            Inhabitants aged 20-64 years with high income (%) *

             

            21.2

            16.9

            Inhabitants aged 20-64 years with high education (%) **

             

            45.9

            30.7

            Mean yearly total income per inhabitant over 16 years (SEK)

             

            209 000

            197 000

            Economic social aid per inhabitant in the city (SEK)

             

            1 391

            1 715

            Unemployment rate aged 20-64 years (%)

            Women

            3.0

            4.0

             

            Men

            4.3

            5.5

            Crime of violence, number per 100 000 inhabitants

             

            976

            1 506

            Participation in National elections (%)

             

            85.0

            81.5

            All data valid for 2006 and from Official Statistics, the Swedish Institute of Public Health and Statistics, Sweden

            *High income refers to the 20% of the inhabitants nationally with the highest income. **High education refers to 12 or more years of education

            Data coding

            There is a long tradition in the Scandinavian countries of documenting diseases in registers and the integrated health care delivery systems are obligated to serve all inhabitants, and each inhabitant is assigned a unique personal code number based on birth date and sex [21]. The health care database can offer data also suitable for population-based epidemiological studies. The county councils in Sweden are required by law to report inpatient data to the Swedish Hospital Discharge register on an annual basis, but national registration of outpatient and primary care data has so far not been implemented [21]. However, in one region and county council in Sweden (Östergötland County Council), patient data from Primary Health Care (PHC), outpatient and, inpatient care (hospital patients) have been recorded for some years in a complete computerized population-based Health Care Register (HCR).

            We conducted a retrospective register study using a health care register to identify diagnosed gastrointestinal problems in medical records. The Health Care Register (HCR) used is based on computerized data files linked by a unique personal code to birth date and sex of all inhabitants in the county. The same personal code is used for all visits and diagnoses in the HCR. The international classification of diseases (ICD) 10-code was used. The selected GI disorders in this study were: Irritable bowel syndrome-constipation (IBS-C) and Irritable bowel syndrome-diarrhoea (IBS-D), respectively (IBS; ICD-K58.0-K58.9), esophageal reflux (GERD; ICD-K21), functional dyspepsia (FD; ICD-K30), functional bowel disease unspecified (FGD-UNS; ICD-K59.0-K59.9), peptic ulcer disease (PUD; ICD-K25-K26), inflammatory bowel disease (IBD; ICD-K50-K51), coeliac disease (ICD-K90) diseases in the gallbladder area (ICD-K80-K83.9), cancers in the GI tract (ICD-C16, C17, C18 and C20) and alcohol-related liver diseases (ARLD; ICD-K70). The attending physician assigned all diagnostic codes. The diagnoses were extracted from the HCR using a case-finding algorithm that retrospectively searched the register from 1/1/2002 to 31/12/2007.

            Data analysis

            All data were stored in a common database and statistically analysed using the SPSS version 17.0 program (SPSS Inc., Chicago, IL, USA). The algorithm captured the cases (one case = one patient) regardless of whether the disorders of interest constituted the main or secondary diagnoses, and it also specified the health care level at which the patient was diagnosed, that is, primary care, outpatient hospital care, and/or inpatients hospital care. The following case definition was applied: the first contact with health care services with a GI diagnosis during the period studied (2002-2007) was regarded as a case. Cumulative incidence rates were calculated and expressed as number of cases per 1,000 inhabitants. The mean population in different age groups for the period 2002-2007 was used as the denominator. We initially estimated the occurrence of gastrointestinal diagnoses for all ages up to the age of 80 in a gender comparison. However, the comparison between the blue-collar and the white-collar cities were only focusing on the population between 25 and 79 years, i.e. the working ages and retirement ages. The numerator for the prevalence calculation was the number of first diagnosed cases identified during the six-year study period. The denominator was the number of inhabitants calculated as the mean number in each age group of the population for the six-year study period. The prevalence rates are presented as numbers per 1,000 inhabitants. We also calculated the Relative Rates (RR) and 95% confidence intervals (CI) and differences between the cities were also calculated with Pearson's chi square.

            The Research Ethics Committee of the Faculty of Health Sciences, Linköping University, Sweden, approved the study (2009).

            Results

            Comparison between the social environments

            The comparison between the twin cities revealed significant differences for functional GI-disorders and peptic ulcer disease (PUD) (ICD-K25 to ICD-K26) that were more frequent in the "white-collar" city than in the "blue-collar city. On the other hand, the diagnoses in the gallbladder area (ICD-K80.0 to ICD-K83.9) were significantly more frequent in the blue-collar city for both sexes and in all age groups. Also alcohol-related liver disease (ARLD) (ICD-K70) among 45-64 year old patients of both sexes was more frequent in the "blue-collar" city; see Table 2 and Table 3.
            Table 2

            Cumulative incidence of GI-diagnoses for males in the "white-collar" and the "blue-collar" city (the Twin cities) in the age-groups 25-79 years, numbers per 1,000 inhabitants

             

            White-collar twin city (L)

            Blue-collar twin city (N)

            GI diagnoses

            Functional diseases

            25-44 years

            45-64 years

            65-79 years

            25-44 years

            45-64 years

            65-79 years

              

            RR (95% CI)

              

            RR (95% CI)

             

            GERD

            Esophageal reflux

            10.8 ***

            20.2 ***

            29.0 ***

            5.6

            8.0

            9.5

             

            1.95 (1.53-2.47)

            2.51 (2.05-3.07)

            3.01 (2.27-3-97)

            1.0

            1.0

            1.0

            FD

            Functional dyspepsia

            10.2**

            13.1***

            16.0**

            7.0

            7.3

            8.6

             

            1.42 (1.17-1.82)

            1.80 (1.44-2.25)

            1.84 (1.34-2.52)

            1.0

            1.0

            1.0

            IBS-D, Irritable Bowel Syndrome - Diarrhoea

            2.0*

            2.1*

            1.4

            1.1

            1.0

            1.0

             

            1.76 (1.00-3.07)

            2.00 (1.12-3.57)

            1.35 (0.88-6.88)

            1.0

            1.0

            1.0

            IBS-C, Irritable Bowel Syndrome - constipation

            3.0*

            3.0*

            2.0

            2.0

            2.0

            2.0

             

            1.64 (1.05-2.56)

            1.56 (1.00-1.46)

            1.0

            1.00

            1.00

            nt

            FGD-UNS

            Functional Bowel Disease unspecified

            5.9

            10.0

            26.0

            7.0

            10.1

            33.0*

             

            1.00

            1.00

            1.00

            1.17 (0.91-1.51)

            1.01 (0.90-1.12)

            1.24 (1.02-1.50)

            PUD, Stomach and Duodenum ulcer

            3.5**

            11.0***

            30.0***

            1.8

            5.7

            15.4

             

            2.00 (1.31-3.06)

            1.92 (1.49-2.47)

            1.95 (1.55-2.47)

            1.00

            1.00

            1.00

            Gallstone, gallbladder inflammation and other diseases in the gallbladder area

            9.2

            18.4

            37.0

            11.5*

            22.2*

            48.0*

             

            1.00

            1.00

            1.00

            1.24 (1.02-1.51)

            1.21 (1.04-1.41)

            1.29 (1.10-1.52)

            Alcohol-related liver diseases

            0.5

            2.4

            4.2

            1.1

            4.6**

            2.4

             

            nt

            1.00

            1.76 (0.96-3.23)

            nt

            1.88 (1.27-2.76)

            1.00

            ***p < 0.0001, **p < 0.001 *p < 0.05 nt = not tested

            Table 3

            Cumulative incidence of GI-diagnoses for females in the "white-collar" and the "blue-collar" city (the Twin cities) in the age-groups 25-79 years, numbers per 1,000 inhabitants

             

            White-collar twin city (L)

            Blue-collar twin city (N)

            GI diagnoses

            Functional diseases

            25-44 years

            45-64 years

            65-79 years

            25-44 years

            45-64 years

            65-79 years

              

            RR (95% CI)

              

            RR (95% CI)

             

            GERD

            Esophageal reflux

            9.1***

            20.6***

            29.0 ***

            3.6

            8.7

            9.2

             

            2.53 (1.88-3.40)

            2.51 (2.05-3.07)

            3.02 (2.32-3-91)

            1.00

            1.00

            1.00

            FD

            Functional dyspepsia

            18.0***

            24.0***

            24.0***

            8.2

            8.0

            10.2

             

            2.18 (1.76-2.66)

            3.04 (2.49-3.72)

            2.34 (1.81-3.02)

            1.00

            1.00

            1.00

            IBS-D, Irritable Bowel Syndrome - Diarrhoea

            7.0***

            5.5***

            5.0 **

            2.6

            2.4

            1.6

             

            2.62 (1.86-3.71)

            2.28 (1.57-3.33)

            3.03 (1.62-5.65)

            1.00

            1.00

            1.00

            IBS-C, Irritable Bowel Syndrome - constipation

            7.0*

            7.0

            6.5

            5.0

            6.0

            4.2

             

            1.41 (1.07-1.87)

            1.15 (0.87-1.50

            1.28 (0.83-1.97)

            1.00

            1.00

            1.00

            FGD-UNS

            Functional Bowel Disease unspecified

            18.0**

            19.0*

            32.0

            13.0

            16.2

            32.0

             

            1.38 (1.16-1.64)

            1.18 (1.00-1.39)

            nt

            1.00

            1.00

            nt

            PUD, Stomach and Duodenum ulcer

            3.0**

            7.5***

            24.0***

            1.0

            4.0

            8.0

             

            2.61 (1.51-4.53)

            1.87 (1.39-2.54)

            2.97 (2.24-3.93)

            1.00

            1.00

            1.00

            Gallstone, gallbladder inflammation and other diseases in the gallbladder area

            25.6

            32.0

            35.0

            35.0***

            44.0***

            47.0**

             

            1.00

            1.00

            1.00

            1.36 (1.21-1.53)

            1.37 (1.22-1.53)

            1.35 (1.16-1.57)

            Alcohol-related liver diseases

            0.3

            0.8

            1.3

            0.2

            1.8*

            0.9

             

            nt

            1.00

            1.35 (0.54-3.35)

            nt

            2.23 (1.16-4.28)

            1.00

            ***p<0.0001, **p<0.001 *p<0.05 nt = not tested

            Sex differences

            Significantly differences between sexes in the total cumulative incidence rates of different gastrointestinal disorders were also seen, the same pattern concerning sex differences were seen in both cities, the total distribution of these differences are illustrated in Figure 1. Women had significantly more FD diagnoses than men, RR = 1.60 (95% CI 1.48-1.73). This trend was also seen for IBS-C, RR = 2.55 (95% CI 2.20-2.95) and IBS-D, RR = 2.61 (95% CI 2.29-3.11) except for the lowest age group, where men tend to have more IBS diagnoses. For unspecified FGD, more diagnoses were seen among women RR = 1.37 (95% CI 1.30-1.45). Significantly more diagnoses of GERD were seen among men in the age groups 25-44 RR = 1.29 (95% CI 1.08-1.52) and 80 + RR = 1.71 (95% CI 1.21-2.28) but not totally. Even peptic ulcer disease were more frequent among men compared to women in the age groups from 25 and older, RR = 1.12 (95% CI 1.02-1.23).
            http://static-content.springer.com/image/art%3A10.1186%2F1476-072X-11-5/MediaObjects/12942_2011_Article_470_Fig1_HTML.jpg
            Figure 1

            Cumulative incidence of GI diagnoses (per 1.000 inhabitants) for females and males in a defined region. (GERD = Esophageal Reflux, FD = Functional Dyspepsia, IBS-C = Irritable Bowel Syndrome--constipation, IBS-D = Irritable Bowel Syndrome--diarrhea, FGD-UNS = Functional Bowel Disease unspecified, PUD = Peptic Ulcer Disease, IBD = Inflammatory Bowel Disease, ARLD = Alcohol Related Liver Disease, C = cancer.).

            Coeliac diagnoses were significantly, RR = 1.57 (95% CI 1.37-1.79), more frequent among women compared to males as well as diagnoses of the gallbladder area, RR = 1.80 (95% CI 1.71-1.91). Even ARLD showed a sex difference, more frequent among men, RR = 2.69 (95% CI 2.05-3.53). Gastric (ICD-C16) and rectal cancers (ICD-C20) were totally more frequent among men, RR = 1.73 (95% CI 1.34-2.21) and RR = 1.27 (95% CI 1.08-1.48), respectively, as illustrated in Figure 1.

            Discussion

            Main findings

            This population-based study revealed differences in the occurrence of GI diagnoses between the studied social environments and also between sexes regardless of the social environment. The comparisons showed that GI-diagnoses that are predominantly related to stressful life events like GERD, IBS, and PUD were more common in the population of the "white-collar" city. Possibly this difference in type of gastrointestinal occurrence between these social environments reflects differences in perceived and actual exposure to stressful life conditions, more predominant in the "white-collar" city. Recent studies of functional gastrointestinal disorders such as IBS, showed that e.g. lack of influence on planning work, anxiety and sleep disruptions were associated with an IBS diagnosis in women and lack of influence on working pace among men [22, 23]. Although this study was only made in the "white-collar "city these attributes were more frequent among the "blue-collar" population in that specific city. These factors might also lead to a stressful life situation that might affect the GI area. PUD and GERD might also, among other things, be induced by stressful life conditions. Another putative candidate mechanism that might explain the differences between the two social environments is a relationship between socioeconomic status and psychiatric disorders on the one hand and psychiatric disorders and FGD on the other hand [3, 22, 23].

            However, certain GI diagnoses like alcohol-related liver diseases and gall-tract disorders were more prevalent in the "blue-collar" city. This may suggest a less healthy life style in its population leading to these problems. This is supported by our previous observations showing that diagnoses predominantly related to life-style problems like coronary heart diseases and chronic obstructive pulmonary disease were more common in the studied blue-collar city [20].

            Discussion under the light of literature

            The observed differences in the occurrence of GI diagnoses between the two social environments are not likely to be explained by chance or by differences in access to health care services. However, it could not be ruled out that health care seeking patterns might differ in the two cities. Both the inpatient and outpatient care is delivered by public health services based on population needs in both cities. So there are no significant differences in the supply of health care facilities like primary care in the two cities. On the marginal, the "white-collar" city population might benefit from being more often referred for investigations requiring technology available only at a university hospital, since these facilities is situated in the "white-collar" city. There might also be variations between the cities in the diffusion of diagnostic skills of doctors within the field of GI disorders. This might impact the assignment of GI complaints in patients seeking advice in the primary care. Anyhow, we believe that the differences seen between the population in the two cities is related to differences in health behaviors, educational levels, psychosocial factors, nutritional habits, life styles in general and specifically alcohol consumption and smoking behaviors [19].

            It is well known that FGD diseases such as IBS and FD and FGD-UNS are more common among women than men, but surprisingly, IBS and FGD-UNS were more frequent among the youngest group of men (data not shown). The explanations of this gender phenomenon must be hypothetic and can differ. It might be randomly due to an unknown factor or due to the fact that more women suffer from IBS [2426] and therefore seek health care more often when their children having the same GI complaints. Our recent study showed that a family history of IBS was related to an IBS diagnosis for both sexes [23]. One hypothesis might be that young men are more vulnerable to psychosocial stressful conditions in everyday life than young women, or quite simply, they have been eating too much, too little or are allergic to certain kinds of food, which might explain the higher frequency of FGD-UNS among boys. The prevalence of GERD was fairly equal between men and women. Alcohol-related liver disease was more frequent among men, since men in general consume more alcohol than women. Coeliac diagnoses were significantly more frequent among women compared to men and most frequent among younger populations. Specially, adult women with coeliac disease continue to seek health care for other complaints, without mentioning their previous coeliac diagnose [27].

            The total number of gall diseases was significantly more frequent among women compared to men except in the oldest age group. The causes of gallstone formation are multifactorial, although some risk factors are permanent, such as being women, increasing age and ethnicity and previous family history of the disease. Other recognized risk factors are a high caloric intake and obesity [2830]. There are two types of gallstones. In the western world, the majority of the stones consist predominantly of cholesterol crystals (80-85%) and the rest black pigment [29]. Brown pigment stones, however, consist of calcium bilirubinate, calcium soaps, mucin and some cholesterol and are the predominant type in East Asia [31]. However, gallstone composition in East Asia has changed in recent decades with an increase in cholesterol gallstones possibly due to changed dietary habits [32]. Studies also show that gallstones are uncommon in children [33]. The risk of getting gallstones increases with age in all ethnic groups [3436]. Women in the USA and Western Europe compared to Asia have a larger risk of this disease most likely due to the composition of the gallstones [3739]. Female hormones as well as increasing obesity for women might explain some of the sex differences found were females are more at risks for gallstones than men [40, 41]. However, this phenomenon diminishes after menopause, which our study also shows, since the frequency is more equal among sexes in the two oldest age groups.

            Peptic ulcer diseases in this study occur more frequently among men in all age groups. These diseases are often induced by Helicobacter pylori (HP) or non-steroid anti-inflammatory drugs (NSAID), two independent risk factors, PUD is often decreasing with age, although a peak often occur at retirement [42, 43]. However, these factors cannot explain differences in occurrence between sexes. One hypothesis might be that men to a larger extent are more stressed and this induces the HP bacteria to act and induce PUD, or men might to a greater extent with increasing age suffer from complaints like arthritis and musculoskeletal problems that require higher consumption of NSAID and acetylsalicylic acid (ASA).

            This study also showed that gastric and rectal cancers occurred more frequently among men of all ages compared to women. Colon and small intestinal cancers were more equally distributed among both sexes, although colon cancer was slightly more frequent among men, but not significantly so. Colorectal cancer is the third most common form of cancer in Sweden [44]. On the other hand, it is also the third leading cause of death in the USA [45]. Studies suggest that there might be sex differences in screening for colorectal cancers, i.e. that physicians may refer men more frequently for screening than women [46]. Women might report greater fear, anxiety, and embarrassment about screening procedures, which could affect the behaviour concerning this kind of screening [4749]. These factors might explain sex differences, but to what extent? Screening for colorectal cancer is recommended in the USA as well as in some countries in Europe, although not in Sweden so far [5052]. However, the etiology of all these GI diseases is beyond the scope of this study.

            Study limitations and strengths

            Possible limitation in this study is that we do not have any measures of individual socio-economic conditions. Living in a certain social environment like a "blue-collar" or a "white-collar" city could only be a proxy for real socioeconomic status. Further limitations in the study are that the data used was not initially collected for research purposes. The diagnoses registered, although they all derive from medical records, could in some cases be regarded as approximate. The strength of this study is that it is based on medical records in computerized data files (HCR) for all inhabitants linked by birth date and sex. The same personal code is used for all visits and diagnoses in HCR. An individual can thus be followed retrospectively or prospectively through the health care system using this personal code. The health care institution where the patient was diagnosed represents all health care levels - primary care, outpatient hospital care, and/or inpatient hospital care which gives a more complete panorama of the health care. Other strengths of this study are that our inclusion method gains reliability through being very general and covering a span of several years and that the number of included patients is high tending to level out possible misclassification within the groups defined as patients. Studies have also shown that general practitioners rarely misdiagnose for instance FGD [5355] in fact, there may be a tendency by the GP's not to set FGD diagnosis such as IBS in primary care. However, a study of the quality and content of the Swedish Hospital Discharge Register indicates 95% coverage of main diagnostic codes in inpatient care in this region in 1986 and 98% in 2002 [56]. Validation of HCR and other administrative data has shown high specificity in registers covering all types of health care [21, 5759]. But a constraint for register data is that misclassifications do occur, including cases that are not recorded because they are overlooked or given incorrect clinical codes. ICD code registration could vary between physicians and health care centers and also between diagnoses [60]. Nevertheless it can be assumed that the data used in this study based on Health Care register (HCR) has high reliability.

            Impact and conclusions

            To conclude, this population-based study revealed differences in the occurrence of gastrointestinal diagnoses between the populations in a "white-collar" and a "blue-collar" city. Gastrointestinal diagnoses that are predominantly related to stressful life events like GERD, IBS and peptic ulcer disease was more common in the population of the "white-collar" city. This might reflect differences in lifestyles, living conditions and factors in working life like differences in heavy, strenuous or even monotonous work of the populations in the two studied cities that constitutes two close but different social environments. Lifestyle-related gastrointestinal diseases like alcohol-related liver diseases and gall-tract disorders were more frequent in the "blue-collar" city. Significant differences in the cumulative incidence rates of the most common gastrointestinal conditions between sexes were also seen. Women tended to have more functional gastrointestinal diagnoses and gall diagnoses, while men had more peptic ulcer diseases and alcohol-related liver diseases. Many of these conditions also tend to increase with age. A forthcoming research project will investigate the validity of diagnose-issue and whether differences in working life conditions between individuals with functional gastrointestinal problems compared to healthy controls in the "white-collar" and the "blue-collar" city might contribute to explain the differences seen in these twin cities.

            Knowledge of the occurrence of gastrointestinal problems in populations is better understood if viewed in a context were the social environment is included. Indicators of the social environment should therefore also be considered in future studies of the occurrence of gastrointestinal problems.

            Abbreviations

            ARLD: 

            Alcohol-related liver disease

            ASA: 

            Acetylsalicylic acid

            CI: 

            Confidence interval

            FD: 

            Functional dyspepsia

            FGD: 

            Functional gastrointestinal diseases

            GERD: 

            Gastroesophageal reflux

            GI: 

            Gastrointestinal

            GPRD: 

            The general practice research database

            HCR: 

            Population based health care register

            HP: 

            Helicobacter pylori

            IBD: 

            Inflammatory bowel disease

            IBS: 

            Irritable bowel syndrome

            IBS: 

            C Irritable bowel syndrome constipation

            IBS: 

            D Irritable bowel syndrome diarrhoea

            ICD: 

            International classification of diseases

            L: 

            Linköping

            N: 

            Norrkoping

            NASID: 

            Non-steroid anti-inflammatory drugs

            PHC: 

            Primary health care

            PUD: 

            Peptic ulcer disease

            RR: 

            Relative risks

            UK: 

            United Kingdom

            UNS: 

            Unspecific.

            Declarations

            Acknowledgements

            The authors would like to thank the members of "the Twincities Research Group" at Linköping University, Sweden for their valuable comments on this paper.

            Authors’ Affiliations

            (1)
            Local Health Care, R & D Unit, County Council of Östergötland, SE-581 85 Linköping University
            (2)
            Dept of Social and Welfare Studies, Campus Norrköping, Linköping University
            (3)
            Dept of Medicine and Health Sciences, Linköping University

            References

            1. Talley NJ, Spiller R: Irritable bowel syndrome: a little understood organic disease?. Lancet. 2002, 360: 555-564. 10.1016/S0140-6736(02)09712-X.View ArticlePubMed
            2. Talley NJ: A unifying hypothesis for functional gastrointestinal disorders: really multiple diseases or one irritable gut. Rev Gastroenterol Disord. 2006, 6: 72-78.PubMed
            3. Camilleri M, Choi MG: Review article, irritable bowel syndrome. Aliment Pharmacol Ther. 1997, 11: 3-15.View ArticlePubMed
            4. Engel GL: The need for a new medical model--a challenge for biomedicine. Science. 1977, 196: 129-136. 10.1126/science.847460.View ArticlePubMed
            5. Faresjö T: Social environment and health-a social epidemiological frame of reference. Scand J Prim Health Care. 1992, 10: 105-110. 10.3109/02813439209014045.View ArticlePubMed
            6. Social determinants of health. Edited by: Marmot M, Wilkinson RG. 1999, Oxford: Oxford University Press
            7. Williams R, Wright J: Epidemiological issues in health need assessments. BMJ. 1998, 316: 1379-1382.PubMed CentralView ArticlePubMed
            8. Statistics Sweden. The Total population Register. Sweden: Statistics Sweden. 2005,http://​www.​ssd.​scb.​se/​databaser/​makro/​start.​asphttp://​www.​ssd.​scb.​se/​databaser/​makro/​start.​asp
            9. Whitehead WE, Palsson O, Levy RR, Feld AD, Turner M, Von Korff M: Comorbidity in Irritable bowel Syndrome. Am J Gastroenterol. 2007, 102: 2767-2776. 10.1111/j.1572-0241.2007.01540.x.View ArticlePubMed
            10. Goff SL, Feld A, Andrade SE, Mahoney L, Beaton SJ, Boudreau DM, Davis RL, Goodman M, Hartsfield CL, Platt R, Roblin D, Smith D, Yood MU, Dodd K, Gurwitz JH: Administrative data used to identify patients with irritable bowel syndrome. J Clin Epidemiol. 2008, 61: 617-621. 10.1016/j.jclinepi.2007.07.013.View ArticlePubMed
            11. Garcìa Rodrìguez LA, Ruigòmez A, Martìn-Merino E, Johansson S, Wallander MA: Relationship between gastroesophaeal reflux disease and COPD in UK primary care. Chest. 2008, 134: 1223-1230. 10.1378/chest.08-0902.View ArticlePubMed
            12. Ruigòmez A, Wallander MA, Johansson S, Rodrìguez LA: Irritable bowel syndrome and gastroesophageal reflux disease in primary care: is there a link?. Dig Dis Sci. 2009, 54: 1086-1089.View Article
            13. Ruigòmez A, Wallander MA, Johansson S, García Rodríguez LA: One-year follow-up of newly diagnosed irritable bowel syndrome patients. Aliment Pharmacol Ther. 1999, 13: 1097-1102. 10.1046/j.1365-2036.1999.00576.x.View ArticlePubMed
            14. Rodrìguez GLA, Ruigòmez A, Wallander MA, Johansson S, Olbe LL: Detection of colorectal tumor and inflammatory bowel disease during follow-up of patients with initial diagnosis of irritable bowel syndrome. Scand J Gastroenterol. 2000, 35: 306-311. 10.1080/003655200750024191.View Article
            15. Macintyre S, MacIver S, Sooman A: Area, class and health, should we focus on places or people?. J Soc Policy. 1993, 22: 213-234. 10.1017/S0047279400019310.View Article
            16. Macintyre S, Ellaway A, Cummins S: Place effects on health, how can we conceptualise, operationalise and measure them?. Soc Sci Med. 2002, 55: 125-139. 10.1016/S0277-9536(01)00214-3.View ArticlePubMed
            17. Diez-Roux AV, Nieto FJ, Muntaner C, Tyroler HA, Comstock GW, Shahar E, Cooper LS, Watson RL, Szklo M: Neighbor environments and coronary heart disease, a multilevel analysis. Am J Epidemiol. 1997, 146: 48-63.View ArticlePubMed
            18. Picket K, Pearl M: Multilevel analysis of neighborhood socio-economic context and health outcomes, a critical review. J Epidemiol Community Health. 2001, 55: 111-122. 10.1136/jech.55.2.111.View Article
            19. Faresjö T, Rahmqvist M: Educational level a crucial factor for good perceived health in the local community. Scand J Public Health. 2010, 38: 605-610. 10.1177/1403494810374676.View ArticlePubMed
            20. Wennerholm C, Grip B, Johansson AK, Nilsson H, Honkasalo ML, Faresjö T: Cardiovascular disease occurrence in two close but different social environments. Int J Health Geogr. 2011, 10: 5-10.1186/1476-072X-10-5.PubMed CentralView ArticlePubMed
            21. Wirehn AB, Karlsson MH, Carstensen JM: Estimating disease prevalence using a populations-based administrative healthcare database. Scand J Public Health. 2007, 35: 424-431. 10.1080/14034940701195230.View ArticlePubMed
            22. Faresjö Å, Grodzinsky E, Johansson S, Wallander MA, Timpka T, Åkerlind I: A population based case - control study of work and psychosocial problems in patients with irritable bowel syndrome-women are more seriously affected than men. Am J Gastroenterol. 2007, 102: 371-379. 10.1111/j.1572-0241.2006.01012.x.View ArticlePubMed
            23. Faresjö Å, Grodzinsky E, Johansson S, Wallander MA, Timpka T, Åkerlind I: Psychosocial factors at work and in everyday life are associated with irritable bowel syndrome. Eur J Epidemiol. 2007, 22: 473-480. 10.1007/s10654-007-9133-2.View ArticlePubMed
            24. Longstreth GF, Wolde-Tsadik G: Irritable bowel syndromes in HMO examines: prevalence, demographics, and clinical correlates. Dig Dis Sci. 1993, 38: 1581-1589. 10.1007/BF01303163.View ArticlePubMed
            25. Zuckerman Mj, Guerra LG, Drossman DA, Foland A, Gregory GG: Comparison of bowel pattern in Hispanics and non-Hispanics whites. Dig Dis Sci. 1995, 40: 1763-1769. 10.1007/BF02212699.View ArticlePubMed
            26. Faresjö Å, Grodzinsky E, Johansson S, Wallander MA, Foldevi M: Patients with bowel syndrome in Swedish primary care. Eur J Gen Prac. 2006, 12: 88-90. 10.1080/13814780600872937.View Article
            27. Roos S, Kärner A, Wilhelmsson S, Hallert C: Women with celiac disease living on a gluten-free diet for years continue to seek more health care--a controlled study. Gut. 2009, 58 (Suppl II): A262-
            28. Sarin SK, Negi VS, Dewan R, Sasan S, Saraya A: High familial prevalence of gallstones in the first-degree relatives of gallstones patients. Hepatology. 1995, 22: 138-141.PubMed
            29. Shaffer EA: Epidemiology of gallbladder stone disease. Best Pract Res Clin Gastroenterol. 2006, 20: 981-996. 10.1016/j.bpg.2006.05.004.View ArticlePubMed
            30. Friedman GD, Kamel WB, Dawber TR: The epidemiology of gallbladder disease: observations in the Framingham study. J Chronic Dis. 1996, 19: 273-292.View Article
            31. Yamashita N, Yanagisawa J, Nakayama F: Composition of intrahepatic calculi, etiological significance. Dig Dis Sci. 1988, 33: 449-453. 10.1007/BF01536030.View ArticlePubMed
            32. Tsunoda K, Shirai Y, Hatakeyama K: Prevalence of cholesterol gallstone positively correlates with per capita daily calorie intake. Hepatogastroenterology. 2004, 51: 1271-1274.PubMed
            33. Shaffer EA, Walker WA, Druie PR: Pediatric gastrointestinal disease. 2000, Hamilton, Canada: BC Decker Inc, 3
            34. Einarsson K, Nilsell K, Leijd B, Angelin B: Influence of age on secretions of cholesterol and synthesis of bile acids by the liver. N Eng J Med. 1985, 313: 277-282. 10.1056/NEJM198508013130501.View Article
            35. Muhrbeck O, Ahlberg J: Prevalence of gallstone disease in a Swedish population. Scand J Gastroenterol. 1995, 30: 1125-1128. 10.3109/00365529509101618.View ArticlePubMed
            36. Chen CY, Lu CL, Huang YS, Tam TN, Chao Y, Chang FY, Lee SD: Age is one of the risk factors in developing gallstone disease in Taiwan. Age and Aging. 1998, 27: 437-441. 10.1093/ageing/27.4.437.View Article
            37. Barbara L, Sama C, Morselli-Labate AM, Taroni F, Rusticali AG, Festi D, Sapio C, Roda E, Banterle C, Puci A: A population study on the prevalence of gallstone disease, the Sirmione study. Hepatology. 1987, 7: 913-917. 10.1002/hep.1840070520.View ArticlePubMed
            38. Acalovschi M: Cholesterol gallstones: from epidemiology to prevention. Postgrad Med J. 2001, 77: 221-229. 10.1136/pmj.77.906.221.PubMed CentralView ArticlePubMed
            39. The Rome Group for Epidemiology and Prevention of Cholelithiasis (GREPCO): The epidemiology of gallstone disease in Rome Italy. Part I. Prevalence data in men. Hepatology. 1988, 8: 904-906.View Article
            40. Jörgensson T, Kay L, Schultz-Larsen K: The epidemiology of gallstones in a 70 year-old Danish population. Scand J Gastroenterol. 1990, 25: 335-340. 10.3109/00365529009095495.View Article
            41. Attili AF, Scafato E, Marchioli R, Marfisi RM, Festi D: Diet and gallstones in Italy: the cross-sectional MICOL results. Hepatology. 1998, 27: 1492-1498. 10.1002/hep.510270605.View ArticlePubMed
            42. Hawkey CJ: Personal review, Helicobacter pylori, NSAIDs cognitive dissonance. Aliment Pharmaco Ther. 1999, 13: 695-702. 10.1046/j.1365-2036.1999.00550.x.View Article
            43. Huang JQ, Sridhar S, Hunt RH: Role of Helicobacter pylori infection and non-steroidal anti-inflammatory drugs in peptic ulcer disease: a meta-analysis. Lancet. 2002, 359: 14-22. 10.1016/S0140-6736(02)07273-2.View ArticlePubMed
            44. Swedish National Board of health and Welfare, Sweden. Cancer incidence in Sweden. 2006,http://​www.​socialstyrelsen.​se/​statisticshttp://​www.​socialstyrelsen.​se/​statistics
            45. Mandel JS, Bond JH, Church TR, Snover DC, Bradley GM, Schuman LM, Ederer F: Reducing mortality from colorectal cancer by screening foe faecal occult blood. Minnesota Colon cancer Control Study. N Eng J Med. 1993, 328: 1365-1371. 10.1056/NEJM199305133281901.View Article
            46. Meissner HI, Breen N, Klabunde CN, Vernon SW: Patterns of colorectal cancer screening uptake among men and women in the United States. Cancer Epidemiol Biomarkers Prev. 2006, 15: 389-394. 10.1158/1055-9965.EPI-05-0678.View ArticlePubMed
            47. Farraye FA, Wong M, Hurwitz S, Puleo E, Emmons K, Wallace MB, Fletcher RH: Barriers to endoscopic colorectal cancer screening: are women different from men?. Am J Gastroenterol. 2004, 99: 341-349. 10.1111/j.1572-0241.2004.04045.x.View ArticlePubMed
            48. Denberg TD, Melhado TV, Coombes JM, Beaty BL, Berman K, Byers TE, Marcus AC, Steiner JF, Ahnen DJ: Predictors of non-adherence to screening colonoscopy. J Gen Intern Med. 2005, 20: 989-995. 10.1111/j.1525-1497.2005.00164.x.PubMed CentralView ArticlePubMed
            49. McQueen A, Vernon SW, Meissner HI, Rakowski W: Risk perceptions and worry about cancer: does gender make a difference?. J Health Commun. 2008, 13: 56-79. 10.1080/10810730701807076.View ArticlePubMed
            50. Smith RA, Von Eschenbach AC, Wender R, Levin B, Byers T, Rothenberger D, Brooks D, Creasman W, Cohen C, Runowicz C, Saslow D, Cokkinides V, Eyre H, ACS Prostate Cancer Advisory Committee, ACS Colorectal Cancer Advisory Committee, ACS Endometrial Cancer Advisory Committee: American cancer society guidelines for the early detection of cancer: update of early detection guidelines for prostate, colorectal and endometrial cancers. CA Cancer J Clin. 2001, 51: 38-75. 10.3322/canjclin.51.1.38.View ArticlePubMed
            51. Boyle P, Autier P, Bartelink H, Baselga J, Boffetta P, Burn J, Burns HJ, Christensen L, Denis L, Dicato M, Diehl V, Doll R, Franceschi S, Gillis CR, Gray N, Griciute L, Hackshaw A, Kasler M, Kogevinas M, Kvinnsland S, La Vecchia C, Levi F, McVie JG, Maisonneuve P, Martin-Moreno JM, Bishop JN, Oleari F, Perrin P, Quinn M, Richards M, Ringborg U, Scully C, Siracka E, Storm H, Tubiana M, Tursz T, Veronesi U, Wald N, Weber W, Zaridze DG, Zatonski W, zur Hausen H: European code against cancer and scientific justification: third version. Ann Oncol. 2003, 14: 973-1005. 10.1093/annonc/mdg305.View ArticlePubMed
            52. Swedish National Board of Health and Welfare. National guidelines for breast, colorectal and prostate cancers.http://​www.​socialstyrelsen.​se/​englishhttp://​www.​socialstyrelsen.​se/​english
            53. Bellini M, Tosetti C, Costa F, Biagi S, Stasi C, Del Punta A, Monicelli P, Mumolo MG, Ricchiuti A, Bruzzi P, Marchi S: The general practitioner's approach to irritable bowel syndrome: from intention to practice. Dig Liver Dis. 2005, 37: 934-939. 10.1016/j.dld.2005.06.011.View ArticlePubMed
            54. Thompson WG, Heaton KW, Smyth GT, Smyth C: Irritable bowel syndrome: the view from general practice. Eur J Gastroenterol Hepatol. 1997, 9: 689-692.View ArticlePubMed
            55. Agreùs L: Rome? Manning? Who Cares?. Am J Gastroenterol. 2000, 95: 2679-2681.View ArticlePubMed
            56. Swedish National Board of Health and Welfare: Patient register. The Hospital Discharge Register. Discharges 1964-2002, Quality and Content. 2004, Stockholm: Swedish National Board of Health and Welfare
            57. Wilchesky M, Tamblyn RM, Huang A: Validation of diagnostic codes within medical services claims. J Clin Epidemiol. 2004, 57: 131-141. 10.1016/S0895-4356(03)00246-4.View ArticlePubMed
            58. Szeto HC, Coleman RK, Gholami P, Hoffman BB, Goldstein MK: Accuracy of computerized outpatient's diagnoses in a Veterans Affairs general medicine clinic. Am J Manag Care. 2002, 8: 37-43.PubMed
            59. Humphries KH, Rankin JM, Carere RG, Buller CE, Kiely FM, Spinelli JJ: Co-morbidity data in outcomes research: Are clinical data derived from administrative databases a reliable alternative to chart review?. J Clin Epidemiol. 2000, 53: 343-349. 10.1016/S0895-4356(99)00188-2.View ArticlePubMed
            60. Hjerpe P, Merlo J, Ohlsson H, Bengtsson Boström K, Lindblad U: Validity of registration of ICD codes and prescriptions in a research database in Swedish primary care: a cross-sectional study in Skaraborg primary care database. BMC Med Inform Decis Mak. 2010, 10: 23-10.1186/1472-6947-10-23.PubMed CentralView ArticlePubMed

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            This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://​creativecommons.​org/​licenses/​by/​2.​0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.