Abstract 226: Association Between Sleep Duration and Mediterranean Diet Score in Costa Rica

Background: Short and long sleep are risk factors for coronary artery disease. One of the mechanistic pathways is likely through diet. While many studies have examined associations between sleep and individual dietary components, few have examined diet patterns. We hypothesized that those with short sleep (< 7 hours/night) and long sleep (>9 hours/night) would have lower adherence to the Mediterranean diet. We also examined the effect of social jetlag, that is, a difference in the sleep duration between weekdays and weekends, on the Mediterranean diet.

Methods: Participants in this study are population based-controls that were recruited for a case-control study on myocardial infarction and matched by sex, age and area of residence. Study participants (1600 men and 569 women) were recruited randomly using data from the National Census and Statistics Bureau of Costa Rica between 1994 and 2004 and therefore are representative of the Costa Rican population within matching strata. Sleep and napping patterns were self-reported by the participants. Social jetlag was defined as a ≥ 1-hour difference in sleep duration from weekdays to weekends. Validated food frequency questionnaires, detailed socio-demographic, medical history and physical activity questionnaires were administered. Alternative Mediterranean Diet (AMED) scores were calculated based on the consumption of vegetables, fruits, whole grains, nuts, legumes, fish, red and processed meat, alcohol and monounsaturated fat-to-saturated fat ratios. We used adjusted linear regression models stratified by sex to study the association between sleep duration, social jetlag and AMED score.

Results: Men and women with short sleep tended to be younger, more educated, non-smokers, diabetic and have lower physical activity compared to those getting optimal hours (≥ 7 and ≤ 9 hours/night) of sleep. Among women, short sleep on weekdays was significantly associated with having a lower AMED score when compared to those with optimal hours of sleep. This association remained unchanged after adjusting for confounders including age, area of residence, education, napping frequency, caffeine intake, smoking status, physical activity and diagnosis of type 2 diabetes mellitus and hypertension (ß, -0.41 and CI, -0.69 to -0.13). Women with short sleep had a lower intake of vegetables, fruits, and legumes that contributed to their lower AMED score. There were about 20% of men and women with social jetlag. Social jetlag was associated with lower AMED scores, but it was not statistically significant amongst men (p=0.08) or women (p=0.15) after adjusting for confounders.

Conclusions: Short sleep is associated with lower adherence to a Mediterranean diet amongst women in Costa Rica. The lack of an association amongst men might imply different biological pathways and residual confounding by lifestyle factors that drive food consumption in men as compared to women.