Chronotype and metabolic syndrome in midlife: findings from the Northern Finland Birth Cohort 1966.

Evening chronotype is known to be associated with various chronic diseases and cardiovascular risk factors. Metabolic syndrome is a group of conditions that together raise the risk of coronary heart disease, diabetes, stroke, and other serious health problems. Only a few studies have been published on the association between chronotype and metabolic syndrome in unselected population data, with conflicting results. The aim of this study was to evaluate the association between chronotype and metabolic syndrome at population level by using unselected Northern Finland Birth cohort 1966 (NFBC1966) database. The study population consists of participants with NFBC66 (n = 5,113, 57% female) at the age of 46 yr old. Chronotype was determined with shortened Morningness-Eveningness Questionnaires and expressed as morning (44%), intermediate (44%), and evening types (12%). Metabolic syndrome was determined according to the definition of International Diabetes Federation. One-way ANOVA, Kruskal-Walli's test, and χ2 tests were used to compare the chronotype groups, followed by logistic regression analysis (adjusted with alcohol consumption, smoking, marital status, level of education, and leisure-time physical activity). In women, the prevalence of metabolic syndrome was statistically significantly higher in the evening type group: 23, 24, and 34% for morning, intermediate, and evening groups, respectively (P < 0.001). In logistic regression analysis, evening chronotype was associated with higher risk of having metabolic syndrome (OR 1.5; CI 95% 1.2 to 2.0). In this population-based birth cohort study, the evening chronotype was independently associated with higher prevalence of metabolic syndrome in women.NEW & NOTEWORTHY Only a few studies have been conducted on the association between chronotype and metabolic syndrome in unselected population data, with conflicting results. In this population-based cohort study of 5,113 participants, the evening chronotype associated with metabolic syndrome in women when there was no such association in men. The result supports a previous South Korean population study of 1,620 participants, in which the association was also found in women, but not in men.

Validation of the Zung self-rating depression scale (SDS) in older adults.

Objective: The main objective of this study was to investigate the psychometric properties of the Zung Self-Rating Depression Scale (SDS) and evaluate screening parameters capability of the SDS with the Beck Depression Inventory (BDI-21) among the elderly population. Design: A population-based study Setting: Community Subjects: 520 adults, aged 72-73 years, living in the city of Oulu, Finland. Main outcome measures: The screening parameters of the SDS questions and BDI-21 for detecting severity of depression. The Mini Neuropsychiatric Interview for diagnosing major depression. Results: The optimal cut-off point for the SDS was 39. The sensitivity and specificity parameters for this cut-off point were 79.2% (95% CI 57.8-92.9) and 72.2% (95% CI 67.9-76.1), respectively. Positive and negative predictive values were 12.5% (95% CI 7.7-18.8) and 98.6% (95% CI 96.7-99.5), respectively. Moreover, there was no statistically significant difference in diagnostic accuracy indices of the cut-off points 39 and 40. In a receiver operating characteristic analysis, the area under the curve was 0.85 (95%CI 0.77-0.92) for the SDS total score and 0.89 (95% CI 0.83-0.96) for the BDI-21 (p = 0.137). Conclusion: Using the traditional cut-off point, the SDS was convenient for identifying clinically meaningful depressive symptoms in an elderly Finnish population when compared with the BDI-21 which is one of the most commonly used depression screening scales. The sensitivity and specificity of these two screening tools are comparable. Based on our study, the SDS is convenient for identifying clinically meaningful depressive symptoms among older adults at the community level. Key points The widely used Zung Self-Rating Depression Scale (SDS) has not previously been validated among elderly people at the community level. The sensitivity and specificity of SDS (cut-off point 39) were 79.2% and 72.2%. The positive and negative predictive values for SDS were 12.5% and 98.6%. SDS is convenient for identifying major depression in an elderly population and regarding sensitivity and specificity comparable to BDI-21.