Introduction and objective.Low levels of serum vitamin D have been associated with increased occurrence of ischemic heart disease (IHD), but findings are inconsistent, e.g.seasonal variation is not always considered in the analyses.The aim of this study was to investigate whether vitamin D is associated with IHD among rural middle-aged men in Sweden when seasonal variation is taken into account.Materials and method.A nested case-control study was performed within a population-based cohort of Swedish farmers and rural residents followed for 20 years.Outcomes were from national health registers.For 276 cases (IHD at any time during follow-up), and for 276 aged-matched controls free of cardiovascular diseases or diabetes, serum levels of vitamin D (25-hydroxyvitamin D 3 ) were analyzed with liquid chromatography/tandem mass spectrometry (LC/MS/MS), in stored blood samples drawn at the baseline survey in 1990-91.The odds ratio (OR) with 95% confidence intervals (CI) of IHD for vitamin D-quartiles (based on measured as well as adjusted for month of sampling) was evaluated in logistic regression models; potential confounders were taken into account.Results.The measured mean vitamin D levels were 27.6 ng/ml(standard deviation (sd)8.2ng/ml) and 28.8 ng/ml (sd 9.0) among cases and controls, respectively.Compared to the quartile with the lowest month-adjusted vitamin D levels, the risk of IHD was significantly lower in the highest quartile (OR=0.46,95% CI 0.25-0.84,p=0.012) in the fully-adjusted model. Conclusion.Rural Swedish men in the highest quartile of serum vitamin D had halved relative risk of IHD, compared to those in the lowest quartile.

BACKGROUND:Farmers have an increased risk for musculoskeletal disorders (MSD) such as osteoarthritis of the hip, low back pain, and neck and upper limb complaints. The underlying mechanisms are not fully understood. Work-related exposures and inflammatory responses might be involved. Our objective was to identify plasma proteins that differentiated farmers with MSD from rural referents.METHODS:Plasma samples from 13 farmers with MSD and rural referents were included in the investigation. Gel based proteomics was used for protein analysis and proteins that differed significantly between the groups were identified by mass spectrometry.RESULTS:In total, 15 proteins differed significantly between the groups. The levels of leucine-rich alpha-2-glycoprotein, haptoglobin, complement factor B, serotransferrin, one isoform of kininogen, one isoform of alpha-1-antitrypsin, and two isoforms of hemopexin were higher in farmers with MSD than in referents. On the other hand, the levels of alpha-2-HS-glycoprotein, alpha-1B-glycoprotein, vitamin D- binding protein, apolipoprotein A1, antithrombin, one isoform of kininogen, and one isoform of alpha-1-antitrypsin were lower in farmers than in referents. Many of the identified proteins are known to be involved in inflammation.CONCLUSIONS:Farmers with MSD had altered plasma levels of protein biomarkers compared to the referents, indicating that farmers with MSD may be subject to a more systemic inflammation. It is possible that the identified differences of proteins may give clues to the biochemical changes occurring during the development and progression of MSD in farmers, and that one or several of these protein biomarkers might eventually be used to identify and prevent work-related MSD.

Introduction: Cholesterol has many important functions in the human body. However, high levels of low-density lipoprotein (LDL) cholesterol are associated with higher risk for cardiovascular disease while high-density lipoprotein (HDL) cholesterol is associated with lower risk. Cross-sectional studies have shown associations between levels of perfluoroalkyl acids (PFAA) and cholesterol levels. The aim of this prospective study was to investigate potential associations between PFAA and cholesterol levels in blood. Methods: We used data from the "FAJ cohort" ("Health through work"), established in Sweden in 1989 encompassing middle-aged men. Participants were examined at two occasions, 1990/91 (n=1782) and 2002/03 (n=1589), including blood samples. A sample of 106 men was randomly drawn among those with no history of heart or endocrine disease and who donated blood at both occasions.. PFAA (PFOA, PFOS and PFNA) were analyzed using liquid chromatography/tandem mass spectrometry (LC/MS/MS). With linear regression models including age and body mass index, we investigated the association of the concentrations of the PFAA (at baseline as well as change over time) on absolute and relative change over time of cholesterol levels (total cholesterol, LDL and HDL). Results: Increased PFNA level in 1990/91 was associated with increased levels of total cholesterol in 2002/03 (p=0.004). In addition, PFOA level in 1990/91 was associated with absolute (p=0.05) as well as relative change (p=0.003) in total cholesterol between the two examinations. There were no significant associations between PFOS and cholesterol. Conclusion: Our prospective study is one of the first showing associations over time between PFAA and cholesterol levels in humans. Further research needs to confirm whether a causal relation exist and investigate mechanisms and biological processes behind.

Background: Cross-sectional studies have shown an association between exposure to perfluoroalkyl substances (PFASs) and coronary heart disease (CHD). These findings need to be evaluated in longitudinal settings.Objectives: To investigate the risk of CHD in relation to PFAS levels in a longitudinal setting among Swedish rural residents.Methods: In a population-based prospective cohort of male farmers and rural residents recruited in 1990-1991, all men who received a CHD diagnosis between 1992 and 2009 were identified from national registers (n=253). For each CHD case, one control, matched for age, was chosen randomly from the cohort. For all cases and controls, levels of eight PFASs at baseline were measured in stored blood samples. In addition, for a subsample, PFAS levels were also measured in serum samples collected at a follow-up in 2002-2003.Results: There were no statistically significant associations between levels of seven of the eight PFASs at baseline and risk for developing CHD. There was a significant association between perfluoroheptanoic acid (PFHpA) and CHD (OR=2.72; 95% CI: 1.52, 4.84) for the 3rd quartile and (OR=2.45; 95% Cl: 1.40, 4.29) for the 4th quartile compared to the lowest quartile. Changes in levels of PFCs between baseline and follow-up did not differ systematically between cases and controls.Conclusions: This longitudinal study does not lend support to the previously reported cross-sectional relationship between PFAS levels and CHD risk. We found a significant association with PFHpA, but this could be a chance finding, considering its chemical resemblance to other PFASs. (C) 2015 Elsevier Inc. All rights reserved.

BACKGROUND:Few studies have examined the risk of type 2 diabetes in various occupational groups. Farmers in Sweden have a low risk of coronary heart disease, but less is known about diabetes.OBJECTIVE:To analyze the cumulative incidence and relative risk of type 2 diabetes among farmers and referents taking lifestyle factors and components of the metabolic syndrome into account.METHODS:In a longitudinal observational cohort study we followed 1,220 farmers, 1,130 rural non-farmer referents and 1,219 urban referents over 20 years. Outcomes were generated from national registers and from two surveys 12 years apart. Baseline data were assessed at the first survey conducted in 1990-91.RESULTS:Farmers had a significantly lower risk of all diabetes compared with urban and rural referents (p<0.05). A total of 91 farmers (8.4%) and 102 non-farming rural referents (11.5%) were identified with type 2 diabetes over the 20 year study period (OR=0.70; 95% CI 0.52-0.95). Fractional analyses of lifestyle factors and components of the metabolic syndrome showed that the low risk of type 2 diabetes among farmers was explained in terms of physical activity and meal quality. Farmers had significantly higher physical capacity (p<0.001) and scored higher in a meal quality index than rural referents (p<0.001).CONCLUSIONS:The prevalence of type 2 diabetes was significantly lower among farmers. The low relative risk was explained by high physical activity and better meal quality, indicating that farmers' lifestyles and their work environment are health-promoting.

The risk of type 2 diabetes (T2D) is related to lifestyle but less is known about how lifestyle factors interact and how they impact the risk when combined. This study was performed to analyze how lifestyle factors relate to the cumulative incidence of T2D in a Swedish rural population. Outcomes were generated from national registers and from two surveys. Two hundred sixty men (11%) with diabetes were found in the registers, and 193 men with T2D were identified in the surveyed population (9.8%). Physical activity (OR for high physical activity=0.55 (95% CI 0.31-0.97) and meal quality (OR for high meal quality=0.58 [95% CI 0.350.99] were significantly related to T2D in the adjusted analyses. Other lifestyle factors had no significant relationship with T2D in this study. An interaction between physical activity and meal quality was revealed, indicating that a healthy lifestyle in one of the aspects does not compensate for an unhealthy choice in the other.

BACKGROUND The knowledge about the intra-individual variations over time of the endocrine disruptors perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) in the general populations is insufficient. AIM The aim of the present study was to estimate the intra-individual variation of PFOS and PFOA between 1990/91 and 2002/03 in men from the general population in Sweden. METHODS Serum samples were collected at two occasions (1990/91 and 2002/2003) in 106 men from the general population in Sweden. The median age of the men in 1990/91 was 54 years (range 41 to 61). PFOS and PFOA concentrations were analyzed in the stored samples at the same occasion by liquid chromatography/tandem mass spectrometry (LC-MS/MS). The limit of detection (LOD) was 0.03 ng/mL for PFOS and 0.02 ng/mL for PFOA. We investigated if there were systematic differences between the two occasions in the PFOS and PFOA concentrations with Wilcoxon paired test. RESULTS All measurements were above the LOD. At the first occasion (1990/91) the median concentrations was 22 ng/mL (quartiles 18-28) for PFOS and 3.7 ng/mL (3.2- 4.7) for PFOA. The corresponding figures at the second occasion (2002/03) were 19 ng/mL (15-24) and 3.4 ng/mL (2.6-4.3), respectively. There were systematic intra-individual differences (p-values below 0.001) in the PFOS and PFOA concentrations between the two occasions. The median decrease was 2.3 ng/mL for PFOS and 0.4 ng/mL for PFOA. The size of the decrease was not associated with the age of the men. CONCLUSIONS Although statistically significant, the decreases of the PFOS and PFOA concentrations were moderate during the investigated period. The continuation of the project will focus on possible determinant that might explain the variation in the intra-individual concentrations.

Objective. To study associations between dairy fat intake and development of central obesity. Design. A prospective population-based cohort study with two surveys 12 years apart. Setting. Nine municipalities selected from different parts of Sweden representing the rural areas in the country. Subjects. 1782 men (farmers and non-farmers) aged 40-60 years at baseline participated in a baseline survey (participation rate 76%) and 1589 men participated at the follow-up. 116 men with central obesity at baseline were excluded from the analyses. Main outcome measures. Central obesity at follow-up defined as waist hip ratio >= 1. Results. 197 men (15%) developed central obesity during follow-up. A low intake of dairy fat at baseline (no butter and low fat milk and seldom/never whipping cream) was associated with a higher risk of developing central obesity (OR 1.53, 95% CI 1.05-2.24) and a high intake of dairy fat (butter as spread and high fat milk and whipping cream) was associated with a lower risk of central obesity (OR 0.52, 95% CI 0.33-0.83) as compared with medium intake (all other combinations of spread, milk, and cream) after adjustment for intake of fruit and vegetables, smoking, alcohol consumption, physical activity, age, education, and profession. The associations between dairy fat intake and central obesity were consistent across body mass index categories at baseline. Conclusion. A high intake of dairy fat was associated with a lower risk of central obesity and a low dairy fat intake was associated with a higher risk of central obesity.

Background. Studies report low prevalence of several health problems among farmers. Health status and psychosocial factors are generally assumed to impact on retirement age and the ability to stay in work. Objectives. To study retirement in a male rural population and to test the hypothesis that farmers retire later than nonfarmers thanks to better health status and advantageous psychosocial factors. Method. The study design was a longitudinal cohort study on farmers and rural nonfarmers with data assessment at two surveys 12 years apart. Analyses were performed with multiple logistic regression models. Results. Among subjects 64 years or younger at survey 2, 93% of the farmers were still working (full or part time) as compared with 76% of the employed nonfarmers. Among those 65 years or older, 64% of the farmers, 33% of nonfarming entrepreneurs, and 6% of employed nonfarmers were still occupationally active. Significant differences in reported diseases and psychosocial factors were found between farmers and nonfarmers, but in the fully adjusted model these variables did not modify the low odds ratios of retirement found for farmers. The farmers adjusted risk (OR) for premature retirement (64 or younger) was 0.30 (95% CI 0.16-0.55) and for standard retirement (65 or older) 0.01 (95% CI 0.00-0.05). Conclusions. Farmers continue to work full or part time around retirement age to a much larger extent than employees. The employment status of farmers may only partly explain this. Health status and psychosocial factors did not impact on the results.

Back pain is a common cause of sick leave. We analyzed how individual, work-related and lifestyle factors predicted sick leave owing to neck or low back pain over a 12-year period. In this prospective cohort study, 1,405 rural middle-aged farmers and non-farmers were surveyed in 1990-1991 (participation rate 76%) and followed up 12 years later (participation rate 68%). The 836 men who reported having experienced unspecific neck or low back pain the year prior to survey 1 were followed up for self-reported sick leave owing to neck or low back problems. Individual, occupational and lifestyle factors and data on acquired specific neck or back diagnosis were included in multiple logistic regression models. Seven percent reported neck or low back related sick leave during the 12 year period. Self-employment was associated with a lower risk of sick leave while sedentary leisure time, snuff use and a specific neck or back diagnosis was associated with a higher risk. Age, education, physical workload, marital status, sense of coherence, smoking, and alcohol consumption were not independently associated with sick leave. The low risk of sick leave among the self-employed is notable from a societal and public health perspective.