Siesta and the risk of coronary heart disease: results from a population-based, case-control study in Costa Rica

Background The siesta (afternoon nap or rest), a common traditional behavio ur in tropical areas, may increase the risk of myocardial infarction (MI) s ince the post siesta cardiovascular response very closely resembles the per iod soon after waking up in the morning when the onset of acute cardiovascu lar events is high. Methods We studied 505 MI survivors and 522 randomly selected controls, mat ched for age, gender, and area of residence, in a population-based case-con trol study in Costa Pica. Participation rates were 97% for cases and 90% fo r controls. All subjects completed a physical activity questionnaire that i ncluded occupational and leisure time components with specific questions on siesta. Five siesta frequency categories (<1/wk, 1-4/wk, 5-6/wk, daily [gr eater than or equal to 1 h and <2 h], and daily [greater than or equal to 2 h and <3:30 h]) were used to calculate the odds ratio (OR) by multiple log istic regression. Results Compared to controls, cases were more likely to take daily siestas (44 versus 35%, P = 0.01), and spend more time per siesta (1:07 +/- 0:04 ve rsus 0:54 +/- 0:04 h:min, P = 0.002). As compared to subjects with the lowe st siesta frequency (<1/wk), the OR for MI among those in the highest categ ory was 1.51 (95% CI : 1.02-2.25, P for trend = 0.006). After adjusting for risk factors, lifestyle, and health history the OR across the siesta categ ories were 1.0, 0.77, 1.28. 1.66, and 1.40 (P for trend = 0.02). Conclusions Our data suggest that the practice of daily siesta is associate d with increased risk of MI.