Chronic sleep insufficiency in women affects insulin sensitivity independently of changes in adiposity: results from a randomized trial
Goals
Lack of sleep is associated with type 2 diabetes, although the causal impact of chronic lack of sleep on glucose metabolism in women is unknown. We investigated whether prolonged mild sleep restriction (SR), similar to short sleep in the real world, affects glucose metabolism in women.
Methodology
Women (20 to 75 years of age) without cardiometabolic diseases and with an actigraphy-confirmed usual total sleep time (TST) of 7 to 9 h/night were recruited to participate in this randomized, crossover study with two phases of 6 weeks: maintenance of adequate sleep (AS) and 1.5 h/night SR.
The results included plasma glucose and insulin levels, HOMA insulin resistance (HOMA-IR) values based on fasting blood samples, as well as the total area under the glucose and insulin curve, the Matsuda index and the provision of an oral glucose tolerance test.
Results
Our sample included 38 women (n = 11 postmenopausal women). Values are reported with ±SEM. Linear models adjusted to baseline outcome values demonstrated that total sleep time (TST) was reduced by 1.34 ± 0.04 h/night with SR versus AS (P < 0.0001).
Fasting insulin (β = 6.8 ± 2.8 pmol/L; P = 0.016) and HOMA-IR (β = 0.30 ± 0.12; P = 0.016) values increased with mild and prolonged insulin restriction. sleep (SR) versus AS, with effects on HOMA-IR more pronounced in postmenopausal women compared with premenopausal women (β = 0.45 ± 0.25 vs. β = 0.27 ± 0.13, respectively; P for interaction = 0.042).
Change in adiposity did not mediate the effects of mild and prolonged sleep restriction (SR) on glucose metabolism or change outcomes in the full sample when included as a covariate.
Conclusions Reducing sleep duration to 6.2 h/night, reflecting the average sleep duration of short-sleeper US adults, for 6 weeks impairs insulin sensitivity, independent of adiposity. The findings highlight that insufficient sleep is a modifiable risk factor for insulin resistance in women that should be targeted by diabetes prevention efforts. |
Graphic summary
Comments
Chronic lack of sleep can increase insulin resistance in otherwise healthy women, with more marked effects in postmenopausal women, according to a study funded by the National Institutes of Health. The findings, published in Diabetes Care , highlight the importance of getting enough sleep to minimize the risk of type 2 diabetes, which can develop when the body does not effectively use a key hormone, insulin, to maintain healthy blood sugar levels.
"Women report sleeping less than men, so understanding how sleep disorders affect their health across the lifespan is critical, especially for postmenopausal women," said Marishka Brown, Ph.D., director of the Center. National Research Center for Sleep Disorders at the National Heart, Lung, and Blood Institute (NHLBI), which co-funded the study with the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), both part of the NIH.
Previous studies have shown that sleep restriction can raise the risk of diseases such as cardiovascular disease, hypertension, and glucose metabolism disorders, which can lead to insulin resistance and type 2 diabetes. However, many of those studies were conducted only in men or focused on severe short-term sleep restriction.
The current study enrolled only women and sought to determine whether mild, prolonged sleep restriction (a reduction of just 1.5 hours each night) increased women’s blood glucose and insulin levels . Insulin helps regulate glucose in the body, and when the body’s cells develop resistance to insulin, they become less able to use it effectively and can cause a person’s risk of prediabetes and type 2 diabetes to increase dramatically.
For the study, researchers recruited 40 women, ages 20 to 75, who had healthy sleep patterns (at least 7 to 9 hours per night), normal fasting glucose levels, but who had elevated risks of disease. cardiometabolic due to being overweight or obese or a family history of type 2 diabetes, increased blood lipids, or cardiovascular disease.
To establish a baseline for the study, the women wore a sensor on their wrists to record their sleep and determine their typical sleep patterns for two weeks and kept nightly sleep logs. The women then completed two six-week study phases in random order: one in which they continued to follow their healthy sleep patterns and another in which sleep was restricted. In the meantime, they took a six-week break to recalibrate.
During the adequate sleep phase, participants maintained their usual bedtime and wake-up times. On average, they slept 7.5 hours a night. In the sleep restriction phase, participants delayed their bedtime by 1.5 hours per night, maintaining their usual wake time. During this phase, they slept 6.2 hours per night, reflecting the average sleep duration of sleep-deficient American adults. At the beginning and end of each phase of the study, participants completed an oral glucose tolerance test to measure blood glucose and insulin levels, along with an MRI to measure body composition.
The researchers found that restricting sleep to 6.2 hours or less per night for six weeks increased insulin resistance by 14.8% among pre- and postmenopausal women, with more severe effects for postmenopausal women: up to 20%. ,1%. In premenopausal women, they found that fasting insulin levels increased in response to sleep restriction, while both fasting insulin and glucose levels tended to increase in postmenopausal women.
"What we’re seeing is that more insulin is needed to normalize glucose levels in women under sleep-restricted conditions, and even then, the insulin may not have done enough to counteract the rise in blood glucose levels." of postmenopausal women," said Marie-Pierre St-Onge, Ph.D., associate professor of nutritional medicine and director of the Center of Excellence for Circadian and Sleep Research at Columbia University Vagelos College of Physicians and Surgeons, in New York City, and lead author of the study. "If this is sustained over time, it is possible that prolonged insufficient sleep among people with prediabetes could accelerate the progression to type 2 diabetes."
The researchers also looked at whether changes in body weight explained the changes they observed in insulin and glucose levels, since people tend to eat more in sleep-restricted states. However, they found that the effects on insulin resistance were largely independent of changes in body weight, and once the women began sleeping their typical 7 to 9 hours a night again, insulin levels and glucose returned to normal.
"This study provides new insights into the health effects of even small sleep deficits in women across all stages of adulthood and racial and ethnic backgrounds," said Corinne Silva, Ph.D., program director of the Division of Diabetes, Endocrinology and Tabolic Diseases at NIDDK. "Investigators are planning additional studies to better understand how sleep deficiency affects metabolism in men and women, as well as explore sleep interventions as a tool in type 2 diabetes prevention efforts."
Funding : This study received funding from NHLBI (R01HL128226, R35HL155670, T32HL007343, R01HL106041, R01HL137234) and NIDDK (R01DK128154, R01DK128154, P30DK063608, R01DK128154), with trial support from the National Center for Advancing Translational Sciences (NCATS; UL1TR001873) .
