Elevated fasting glucose protective against osteoporosis

Individuals with high fasting glucose levels have a decreased risk of developing osteoporosis, a study suggests.

The analysis was based on a Korean cohort (mean age, 63.9 years; mean body mass index [BMI], 24.1 kg/m²) of 59,936 men and 36,690 women registered in a national health insurance database. They were grouped according to their baseline fasting glucose (quartile 1, <88 mg/dL; quartile 2, 88–96 mg/dL; quartile 3, 97–107 mg/dL; and quartile 4, ≥108 mg/dL) and glycaemic status (normal, impaired fasting glucose, and diabetes mellitus [DM]).

There were 10,643 (11.01 percent) incident cases of osteoporosis recorded over 399,848.2 person-years of follow-up. Individuals who did versus did not develop the systemic skeletal disorder were older (65.6 vs 63.4 years), more likely to be men (67.6 percent vs 17.0 percent) and less likely to be women (32.4 percent vs 83.0 percent), had greater BMI and waist circumference, and had higher blood pressure and cholesterol levels, among others.

In a multivariate Cox proportional hazard model, elevated fasting glucose conveyed a lower risk of osteoporosis. The risk significantly decreased above the fourth quartile of fasting glucose in men (vs quartile 1: hazard ratios [HRs], 0.80 in quartile 4, 0.88 in quartile 3, and 1.04 quartile 2) and above the third quartile in women (vs quartile 1: HRs, 0.82 in quartile 4, 0.91 in quartile 3, and 0.95 quartile 2).

Osteoporosis risk was lower in men and women with impaired fasting glucose (HR, 0.84, 95 percent confidence interval [CI], 0.76–0.94 and HR, 0.93, 95 percent CI, 0.89–0.98, respectively) and DM (HR, 0.77, 95 percent CI, 0.65–0.91 and HR, 0.75, 95 percent CI, 0.69–0.81) than in individuals with normal glucose.

In light of the findings, impaired fasting glucose is believed to contribute to compensatory hyperinsulinaemia, which helps lower the risk of osteoporosis through anabolic effect of insulin.