Sleeping Difficulty and Type 2 Diabetes
Is difficulty sleeping associated with risk for type 2 diabetes?
Data from the Nurses’ Health Study (NHS) and Nurses’ Health Study II (NHSII) were used for the present analysis. Both studies are prospective cohorts; NHS was initiated in 1976, enrolling female nurses, ages 30-55 years. NHSII was initiated in 1989 and included female nurses, ages 25-42 years. Both cohorts completed mailed questionnaires, which included information on health behaviors including sleep in addition to height, weight, and cardiovascular risk factors. Women without a history of diabetes, cardiovascular disease, and cancer at baseline were included. Sleeping difficulty was assessed (in year 2000 for NHS and year 2001 for NHSII) as having difficulty falling or staying asleep “all of the time” or “most of the time.”
A total of 133,353 women were included in this analysis. The percentage of women who reported sleeping difficulty (having difficulty falling or staying asleep all or most of the time) was 5.9% in NHS and 4.8% in NHSII. Sleeping difficulty was associated with a higher body mass index (BMI), less physical activity, lower dietary quality score, shorter sleep duration, more frequent snoring, more common use of minor tranquilizers, more frequent excessive daytime sleepiness, higher likelihood of shift work, and higher prevalence of hypertension and depression symptoms. A total of 6,407 incident cases of type 2 diabetes were identified during up to 10 years of follow-up. Risk for type 2 diabetes was hazard ratio [HR], 1.45 (95% confidence interval [CI], 1.33-1.58) for women with sleeping difficulty compared to women without sleeping difficulty after adjustment for lifestyle factors at baseline. After further adjustment for hypertension, depression, and BMI, this association between sleep difficulty and type 2 diabetes was somewhat attenuated, but remained significant (HR, 1.22; 95% CI, 1.12-1.34). Women who reported all four sleep conditions (sleeping difficulty, frequent snoring, sleep duration ≤6 hours, and sleep apnea in NHS or rotating shift work in NHSII) had more than a fourfold increased likelihood of type 2 diabetes (HR, 4.17; 95% CI, 2.93-5.91).
The investigators concluded that sleeping difficulty was significantly associated with type 2 diabetes. This association was partially explained by associations with hypertension, BMI, and depression symptoms, and was particularly strong when combined with other sleep disorders.
These data support the need for providers to address good sleep hygiene among adult patients. Further research regarding interventions to promote healthy sleep habits is warranted.
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