A recent study used longitudinal data to investigate current and future risks of metabolic syndrome and its potential links with sleep duration and insomnia.
Metabolic syndrome (MetS) is a disease that is diagnosed in those who have metabolic abnormalities, such as hypertension and abdominal obesity. Short and long sleep duration are known predictors of adverse medical outcomes.
A study published in BMC Endocrine Disorders found that sleep duration and insomnia had an effect on the current and future risk of MetS in postmenopausal women.
Data from the Women’s Health Initiative (WHI), a prospective study of postmenopausal women aged 50 to 79 years, was used for this study. All women reported their own sleep duration, from 6 or fewer hours per night to 10 or more hours per night. The WHI Insomnia Rating Score was also used to determine how often the participants had trouble falling asleep; if they woke up several times a night, woke up earlier than planned, or had trouble getting back to sleep; and how restful sleep was in the past 4 weeks.
Age, race, education level, marital status, and chronic disease presence were collected from the group. All participants were also asked if they used any medication or alcohol at night to help sleep. Waist circumference and body mass index (BMI) were taken for each participant. Participants were excluded if they had a history of diabetes or were missing baseline information.
There were 5159 participants with sleep duration data that were included in the study, of which 5063 had data on insomnia. Women with MetS were more likely to have a higher BMI, depression, low alcohol consumption, low levels of physical activity, longer sleep hours, insomnia, and more frequent use of sleep medication.
Positive associations were found between the following:
There was a borderline positive association between insomnia and MetS (OR, 1.14; 95% CI, 0.99-1.31) and a positive association with waist circumference greater than 88 cm (OR, 1.18; 95% CI, 1.03-1.34) and fasting glucose (FG) of 100 mg/dL and higher (OR, 1.17; 95% CI, 1.02-1.35).
There was a positive association between sleep duration of 9 or more hours and MetS in both strata of insomnia (insomnia, OR, 2.89; 95% CI, 1.39-6.01; no insomnia, OR, 1.54; 95% CI, 1.03-2.00 in each strata, respectively), while women without insomnia had a positive association between sleep duration of 9 or more hours and waist circumference above 88 cm and TG of 150 mg/dL or higher (OR, 1.42; 95% CI, 1.02-1.98; and OR, 1.47; 95% CI, 1.04-2.03, respectively).
Short sleep duration of 6 to less than 7 hours and insomnia were associated with a waist circumference above 88 cm (OR, 1.31; 95% CI, 1.06-1.61). The odds of having FG of 100 mg/dL and above was higher in those without insomnia and less than 6 hours of sleep duration (OR, 1.38; 95% CI, 1.00-1.90) and for those with insomnia and 7 to less than 8 hours of sleep (OR, 1.36; 95% CI, 1.05-1.76).
There were some limitations to this study. The group of women in the WHI may not represent all postmenopausal women in the general population, and data were only available data for a portion of the subjects in the study, which limits the power of the analysis. Sleep duration was also self-reported and is therefore subject to misclassification.
The researchers concluded that current and future risks of MetS were linked to sleep duration in postmenopausal women, which highlights the importance of healthy sleep duration.
Peila R, Xue X, Cespedes Feliciano EM, et al. Association of sleep duration and insomnia with metabolic syndrome and its components in the Women’s Health Initiative. BMC Endocr Disord. 2022;22:228. doi:10.1186/s12902-022-01138-9