Introduction: Health care and research in rural populations are often limited due to poor infrastructure and small sample sizes. However, such populations have a need for medical care and can be of great value when studying the health effects of lifestyle and genetic factors. The Northern Sweden Population Health Study (NSPHS) is a paradigmatic study that combines a survey of the health status and specific needs of the community with basic research into the environmental and genetic determinants of non-communicable diseases. This article presents the NSPHS results on lifestyle, subclinical, and clinical measures and gives a review of the past contributions of this study to our understanding of the genetic determinants of disease in international collaborations.
Methods: A population-representative, cross-sectional sample (n=656) was examined from the Karesuando parish in Northern Sweden north of the Arctic Circle. The population consists of individuals living a traditional, subsistence-based lifestyle (TLS, n=96), mainly based on reindeer herding, hunting and fishing, and others following a modern, more industrialized lifestyle (MLS, n=560), similar to other western European countries. Subgroups with a modern versus traditional lifestyle were compared separately in men and women, highlighting differences in lifestyle (eg diet, physical activity), subclinical (eg blood circulation, blood lipids, lung function) and clinical measures (eg disorders of the cardiovascular, metabolic, and musculoskeletal system).
Results: TLS men and women consumed much more game meat (Men: 71 vs 194 g/day, p=0.0011; Women: 56 vs 140 g/day, p=0.0020) and less non-game meat (Men: 88 vs 42 g/day, p=1.4x10(-7); Women: 81 vs 42 g/day, p=0.026) compared with the respective MLS group. TLS men consumed less milk (p=4.2x10(-4)), and TLS women less vegetables (p=0.042). TLS men reported more physical activity at work (p=0.042) and TLS women less physical activity at leisure (p=0.0023). Total cholesterol (Men: 220 vs 244 mg/dl, p=0.0031; Women: 225 vs 246 mg/dl, (p=0.049) and LDL cholesterol levels (Men: 134 vs 153 mg/dl, p=0.012; Women: 133 vs 146 mg/dl, p>0.05) were higher in the blood serum of TLS men and women than in the MLS comparison group. While TLS women showed a higher rate of myocardial infarction (5% vs 16%, p=0.024), TLS men reported a dramatically higher frequency of body pain consistently, for example in the lower back (0% vs 25%; p>0.05).
Conclusions: A consistent pattern was found of differences between individuals living a traditional versus modern lifestyle and between the sexes, identifying specific health risks for each group. Women with a traditional lifestyle were exposed to a greater risk for cardiovascular disease (especially myocardial infarction) and men with a traditional lifestyle reported higher rates of orthopedic symptoms (eg body pain). We also show that studies of rural populations can make a substantial contribution to basic research into understanding the environmental and genetic determinants of disease. The European Special Populations Research Network (EUROSPAN) provided an excellent example of a platform combining studies of rural populations from different parts of Europe that can leverage these for collaboration with large international consortia.