Higher serum 25-hydroxyvitamin D concentrations are related to a reduced risk of depression.

Vitamin D has been suggested to protect against depression, but epidemiological evidence is scarce. The present study investigated the relationship of serum 25-hydroxyvitamin D (25(OH)D) with the prevalence of depressive and anxiety disorders. The study population consisted of a representative sample of Finnish men and women aged 30-79 years from the Health 2000 Survey. The sample included 5371 individuals, of which 354 were diagnosed with depressive disorder and 222 with anxiety disorder. Serum 25(OH)D concentration was determined from frozen samples. In a cross-sectional study, a total of four indicators of depression and one indicator of anxiety were used as dependent variables. Serum 25(OH)D was the risk factor of interest, and logistic models used further included sociodemographic and lifestyle variables as well as indicators of metabolic health as confounding and/or effect-modifying factors. The population attributable fraction (PAF) was estimated. Individuals with higher serum 25(OH)D concentrations showed a reduced risk of depression. The relative odds between the highest and lowest quartiles was 0.65 (95% CI 0.46, 0.93; P for trend = 0.006) after adjustment for sociodemographic, lifestyle and metabolic factors. Higher serum 25(OH)D concentrations were associated with a lower prevalence of depressive disorder especially among men, younger, divorced and those who had an unhealthy lifestyle or suffered from the metabolic syndrome. The PAF was estimated to be 19% for depression when serum 25(OH)D concentration was at least 50 nmol/l. These results support the hypothesis that higher serum 25(OH)D concentrations protect against depression even after adjustment for a large number of sociodemographic, lifestyle and metabolic factors. Large-scale prospective studies are needed to confirm this finding.

Reduced risk of Parkinson's disease associated with lower body mass index and heavy leisure-time physical activity.

The risk factors for Parkinson's disease (PD) are not well established. We therefore examined the prediction of various lifestyle factors on the incidence of PD in a cohort drawn from the Finnish Mobile Clinic Health Examination Survey, conducted in 1973-1976. The study population comprised 6,715 men and women aged 50-79 years and free of PD at the baseline. All of the subjects completed a baseline health examination (including height and weight measurements) and a questionnaire providing information on leisure-time physical activity, smoking, and alcohol consumption. During a 22-year follow-up, 101 incident cases of PD occurred. The statistical analyses were based on Cox's model including age, sex, education, community density, occupation, coffee consumption, body mass index (BMI), leisure-time physical activity, smoking and alcohol consumption as independent variables. At first, BMI was not associated with PD risk, but after exclusion of the first 15 years of follow-up, an elevated risk appeared at higher BMI levels (P for trend 0.02). Furthermore, subjects with heavy leisure-time physical activity had a lower PD risk than those with no activity [relative risk (RR) 0.27, 95 % confidence interval (CI) 0.08-0.90]. In variance with findings for other chronic diseases, current smokers had a lower PD risk than those who had never smoked (RR 0.23, 95 % CI 0.08-0.67), and individuals with moderate alcohol intake (at the level of <5 g/day) had an elevated PD risk compared to non-drinkers. The results support the hypothesis that lifestyle factors predict the occurrence of Parkinson's disease, but more research is needed.

Self-administered questionnaire is a reliable measure of coffee consumption.

BACKGROUND: The objective of this study was to assess the agreement and repeatability of 2 methods of measuring habitual coffee consumption, and to examine their homogeneity with respect to socioeconomic and lifestyle factors. METHODS: Data on coffee consumption were collected from 4254 subjects by means of a health questionnaire (HQ) and a 1-year dietary history interview (DHI), the latter of which was used as the reference method during the Finnish Mobile Clinic Health Examination Survey conducted in 1973-1976. Short-term repeatability of the methods was assessed using data from 286 and 93 subjects who repeated the HQ and the DHI, respectively, after an interval of 4 to 8 months. The strength of agreement between the 2 methods and between the repeated measurements was estimated using intraclass correlation coefficients (ICCs). RESULTS: The ICC was 0.86 for the agreement between the HQ and the DHI, and 0.77 and 0.85 for the repeatability of the HQ and the DHI, respectively. There were no statistically significant systematic differences in mean intake values between the 2 methods or between repeated measurements. In subgroup analysis of background variables, there were only minor differences in agreement and repeatability, with somewhat higher ICC values among subjects with a healthier lifestyle and higher education. CONCLUSIONS: The high reliability and homogeneity of the health questionnaire make it a useful tool for measuring habitual coffee consumption for the purposes of epidemiological research.