P Magnus1, A Eskild. 1. Section of Epidemiology, National Institute of Public Health, Oslo, Norway.
Abstract
OBJECTIVE: To obtain evidence for seasonal variability in pre-eclampsia using the assumption that environmental factors may have a role in the causal mechanisms. DESIGN: Cross sectional population-based study. POPULATION: All 1,869,388 deliveries in Norway in the years 1967 to 1998. METHOD: For each month, the percentage of births complicated by pre-eclampsia was calculated. The relative risks of pre-eclampsia by month of delivery were estimated as odds ratios using the month with lowest risk as the reference category. RESULTS: Mothers of children born in August had the lowest risk of pre-eclampsia, and the risk was highest in the winter months (for December adjusted OR: 1.26, 95% CI 1.20-1.31). This pattern was independent of parity. maternal age, year and place of living. CONCLUSION: The finding may provide a new clue for understanding the causes of pre-eclampsia. Environmental factors that show a similar seasonal variation should be investigated as possible causes.
OBJECTIVE: To obtain evidence for seasonal variability in pre-eclampsia using the assumption that environmental factors may have a role in the causal mechanisms. DESIGN: Cross sectional population-based study. POPULATION: All 1,869,388 deliveries in Norway in the years 1967 to 1998. METHOD: For each month, the percentage of births complicated by pre-eclampsia was calculated. The relative risks of pre-eclampsia by month of delivery were estimated as odds ratios using the month with lowest risk as the reference category. RESULTS: Mothers of children born in August had the lowest risk of pre-eclampsia, and the risk was highest in the winter months (for December adjusted OR: 1.26, 95% CI 1.20-1.31). This pattern was independent of parity. maternal age, year and place of living. CONCLUSION: The finding may provide a new clue for understanding the causes of pre-eclampsia. Environmental factors that show a similar seasonal variation should be investigated as possible causes.
Authors: Lisa M Bodnar; Janet M Catov; Hyagriv N Simhan; Michael F Holick; Robert W Powers; James M Roberts Journal: J Clin Endocrinol Metab Date: 2007-05-29 Impact factor: 5.958