Higher nocturnal melatonin secretion was associated with greater insulin sensitivity and a lower prevalence of insulin resistance in a study analyzing the data of more than 1,000 women without hypertension, type 2 diabetes or obesity, according to researchers.

Previous studies suggest that melatonin may play a role in glucose metabolism, according to Ciaran J. McMullan, MD, of the renal division in the department of medicine at Brigham and Women’s Hospital in Boston, and colleagues.

The researchers measured the main melatonin metabolite, 6-sulfatoxymetaltonin, through urine concentrations to estimate an association between endogenous nocturnal melatonin secretions.

The researchers included women aged 32 to 52 years (n=1,075) from the Nurses’ Health Study II (1997 to 1999) without diabetes, hypertension, or malignancy in their analysis.

According to data, adjustments were made for age, BMI, smoking, physical activity, alcohol intake, dietary glycemic index, family history of diabetes, blood pressure, total cholesterol, uric acid and estimated glomerular filtration rate (eGFR). After these adjustments, the OR for insulin resistance among women in the highest quartile of urinary 6-sulfatoxymelatonin:creatinine ratio was 0.45 (95% CI, 0.28-0.74) compared with women in the lowest quartile, researchers wrote.

These data indicate that higher nocturnal melatonin secretion was inversely associated with insulin levels and insulin resistance.

“Nocturnal melatonin secretion has been shown to be disrupted by sleep disorders. Thus, our finding that lower nocturnal melatonin secretion is associated with insulin resistance may be a potential mechanism explaining the previously described relationship between disruption of normal sleep pattern and incidence of diabetes,” McMullan and colleagues wrote.

However, due to the observational nature of this study, the researchers suggest further studies to confirm this association.

Source: Endocrine Today