Environmental Health, Environmental Justice
Seasonality of Metabolic Syndrome Characteristics in the Old Order Amish
Jared Fisher (School of Public Health (UMD) Epidemiology and Biostatistics Doctoral Student)
PURPOSE: Prior studies have found that Metabolic Syndrome (MetS) characteristics can vary by season. In order to test if these findings hold true in a predominantly rural/agricultural population, we examined the seasonality of MetS characteristics in a cross-sectional sample of Old Order Amish from Lancaster County, Pennsylvania. This population is genetically homogeneous and of European ancestry with high levels of physical activity, limited medication use, and rates of obesity comparable to the national average. METHODS: We used criteria from the U.S. National Cholesterol Education Program Adult Treatment Panel III (ATPIII) to define MetS as the presence of at least three of the following factors: abdominal obesity, elevated blood pressure, elevated fasting plasma glucose, high serum triglycerides, and low high-density cholesterol (HDL) levels. We used analysis of covariance (ANCOVA) procedures to determine seasonal differences in means and proportions in MetS characteristics while adjusting for age and stratifying by gender. Significance-level adjustments were made for post-hoc group comparisons. RESULTS: The overall prevalence of MetS was 12.4% among 2,438 participants recruited from 1995-2007. Both systolic and diastolic blood pressure readings were higher in fall and winter than in spring and summer (p-values=0.004 and 0.008, respectively). While there were no significant seasonal differences among means for fasting glucose, serum triglycerides, or waist circumference, mean values of certain lipids (LDL, HDL, and total cholesterol) were significantly higher in winter for Old Order Amish men but not for women. CONCLUSIONS: Though there was a relatively low prevalence of MetS in this population, proportions of certain MetS characteristics varied by season. Further analysis may consider whether seasonal differences in time spent outside, physical activity, or other factors can explain the gender-specific findings.
Importance to public health: