The association between the Framingham risk score and sleep: a São Paulo epidemiological sleep study

Sleep is an important factor in the maintenance of cardiovascular integrity. It seems that cardiovascular injury and sleep impairment is another chicken or egg puzzle and we hypothesized that the higher the cardiovascular risk factors the higher the sleep impairment. Therefore, the goal of this study is to analyze the sleep profile of a general population based on cardiovascular risk stratification.

This population-based survey used a probabilistic three-stage cluster sample of Sao Paulo inhabitants to represent the population. A sample size of 1056 volunteers was defined in order to allow for prevalence estimates with 3% precision. From the 1101 selected and interviewed participants, a complete full-night polysomnogram (PSG) was performed in 1042 participants as well as clinical evaluation and blood samples analyses to assess Framingham risk score.

Nine hundred four subjects were classified according the Framingham score and were included in the analyses. A total of 91.7% were classified as a low risk, 5.8% in the intermediate, and 2.4% in the high risk groups according to Framingham score. All polisomnographic parameters were different between groups, except those related to REM sleep parameters. AHI were greater in the high risk compared to the intermediate and low risk groups (23.9 ± 2.8; 17.7 ± 1.8; 7.2 ± 0.5, respectively, p<0.001), as well as a lower total sleep time in minutes (295.3 ± 16.2; 338.4 ± 10.2; 347.4 ± 2.6, respectively, p=0.01). Sleep efficiency in percentage also exhibits a reduction between groups (67.6 ± 2.5; 78.4 ± 1.6; 82.9 ± 0.4, respectively, p<0.001). After adjustment for confounder factors age (p<0.001) and sleep efficiency (p=0.06) remained strongly associated with high risk population.

High Framingham risk score was associated with poor sleep efficiency and aging.