Adolescent Girls in Maine Are at Risk for Vitamin D Insufficiency
Abstract
The objective was to determine the seasonal fluctuations in serum 25-hydroxyvitamin D (25-OHD) in a group of healthy adolescents living in a northern climate. Twenty-three 9- to 11-year-old girls participated in the study from September 2000 to March 2003. Serum 25-OHD and parathyroid hormone levels were measured each September and March. Dietary intake of vitamin D was assessed each summer and winter. Summer-sun exposure was evaluated using reports of time spent outdoors. The mean decrease in serum 25-OHD from September to March was 28%. Vitamin D insufficiency (at least one serum 25-OHD level <50 nmol/L) was observed in 11 of 23 (48%) subjects. Four of 23 subjects (17%) exhibited vitamin D insufficiency in both September and March. Mean parathyroid hormone levels increased 4 pg/mL (15%) from September to March. Vitamin D intakes need to be increased in winter at northern latitudes.
Address correspondence to: Susan S. Sullivan, DSc, RD, Department of Food Science and Human Nutrition, University of Maine, 5735 Hitchner Hall, Orono, ME 04469.
This study was funded by the Maine Dairy and Nutrition Council, the University of Maine Faculty Research Funds, and NIH grant MORR00533. The authors thank Lori Fowler, Julie Burgess, Jennifer Cobb, Kate Yerxa, and Beth Gluck for assisting with data collection, and Jeff Mathieu for analyzing the serum samples.
This study was funded in part by the Maine Dairy and Nutrition Council, which has close ties to the milk processing industry in Maine. Dr Michael F. Holick is an Academic Associate for Nichols/Quest Diagnostics, San Clemente, CA.
ABSTRACT