Sufficient Sleep Duration Contributes to Lower Cardiovascular Disease Risk in Addition to Four Traditional Lifestyle Factors: The MORGEN Study

Study Questions:

Does sufficient sleep duration further reduce cardiovascular disease (CVD) incidence in addition to traditional lifestyle factors?

Methods:

The MORGEN (Monitoring Project on Risk Factors for Chronic Diseases) project was carried out in three cities in the Netherlands between 1993 and 1997, with 10,448 men and 12,652 women ages 20-65. The response was 45%. Participants were excluded for restricted physical activity, prevalent cardiovascular disease (CVD), diabetes, pregnancy at baseline, extremely low or high energy intake, or no information on lifestyle factors. After exclusions, 6,672 men and 7,967 women remained. Lifestyle factors were assessed by validated questionnaires. Sufficient sleep was defined as ≥7 hours per 24-hour period. Participants were followed for first nonfatal CV events, death, or emigration from National Medical Register or Dutch Hospital Discharge data, until 2008.

Results:

Participants were on average 42 years of age at baseline, and 46% were male. Of the total population, 52% were sufficiently physically active, 37% consumed a healthy diet, and 91% of the men and 78% of the women consumed alcohol. Approximately 65% were nonsmokers, and 80% of the men and 86% of the women slept sufficiently. The distribution of healthy lifestyle factors was similar for both men and women; 6% adhered to none or one healthy lifestyle factor, and 12% adhered to all five healthy lifestyle factors. During a mean follow-up of 12 years, 607 composite CVD events occurred: 129 fatal events (21%), 367 nonfatal myocardial infarctions (60%), and 111 nonfatal strokes (18%). Those with the four traditional healthy lifestyle factors had a 57% lower risk of composite CVD (hazard ratio [HR], 0.43; 95% confidence interval [CI], 0.31-0.59) and a 67% lower risk of fatal CVD (HR, 0.33; 95% CI, 0.16-0.68) compared with those with none or one healthy lifestyle factor. Sleeping sufficiently in addition to the four traditional lifestyle factors resulted in a 65% lower risk of composite CVD (HR, 0.35; 95% CI, 0.23-0.52), and an 83% lower risk of fatal CVD (HR, 0.17; 95% CI, 0.07-0.43).

Conclusions:

The authors concluded that sufficient sleep and adherence to all four traditional healthy lifestyle factors were associated with lower CVD risk. When sufficient sleep duration was added to the traditional lifestyle factors, the risk of CVD was further reduced.

Perspective:

This was a large prospective cohort study including both men and women from a general population with broad ages and a long follow-up. Although lifestyle factors were self-reported and were assessed only once during the study, and therefore may have changed during the follow-up period, this is the first study to investigate whether the addition of sufficient sleep to traditional lifestyle factors can contribute to associated CVD. If confirmed in other study populations, these results could have a substantial impact on the public’s attention to sufficient sleep in addition to traditional lifestyle factors to reduce associations with fatal and nonfatal CVD.

Clinical Topics: Sleep Apnea

Keywords: Cardiovascular Diseases, Sleep, Netherlands, Questionnaires


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