Elevated vitamin B12 levels confer insomnia risk in diabetic patients

Vitamin B12 concentrations in type 2 diabetes mellitus (T2DM) patients are linked to the incidence of insomnia and help pinpoint those who are likely to develop the condition according to a study.

The study involved 418 T2DM patients. Researchers measured clinical and biochemical parameters, as well as micronutrient levels, in each participant. They also assessed insomnia and sleep quality using the Athens Insomnia Scale and Pittsburgh Sleep Quality Index (PSQI), respectively.

Of the patients, 24.16 percent had insomnia. This group were more likely to be older, female, have a lower proportion of alcohol drinkers, and a longer duration of diabetes compared with the noninsomniac control group. Moreover, the patients with insomnia had lower Hb levels.

There were between-group differences in body mass index, blood pressure, glycaemic control (HbA1c), β-cell function (fasting C-peptide), pituitary-thyroid hormones, and pituitary-adrenal hormones, among others.

The proportion of patients taking supplements was also similar between the two groups, except for mecobalamin (an active form of vitamin B12) being used more commonly in the insomniac group. As expected, patients with insomnia exhibited much worse sleep quality based on the global PSQI score and on each subscale score.

In terms of micronutrients, only vitamin B12 levels differed significantly between the insomnia and control groups. Multivariable logistic regression analysis confirmed that elevated levels of serum vitamin B12 was an independent risk factor for insomnia (odds ratio, 1.61, 95 percent confidence interval, 1.06–2.45; p=0.03). Vitamin B12 levels predicted insomnia risk at a cutoff value of 517.50 pg/ml (p=0.01; area under the operating characteristic curve, 0.61; standard error, 0.04).

Moreover, increased vitamin B12 levels in patients with insomnia were closely correlated with the use of mecobalamin.