Sex differences between mid-life glycaemic traits and brain volume at age 70: a population-based study

Higher HbA1c in mid-to-later life has been associated with smaller whole brain volume (WBV) in older women but not men. We explored whether this association was replicated using different markers of (i) glycaemic health [fasting glucose, insulin resistance (HOMA2-IR), and β-cell function (HOMA-%B)] and (ii) brain structure (white or grey matter volume). 453 participants (51% men) from the 1946 British Birth Cohort had glycaemic measures (at age 60-64) and MRI measures (at age ∼70). In women, higher fasting glucose and insulin resistance at age ∼60 were weakly associated with lower WBV at age ∼70 [eg, fasting glucose: β* = -0.07 (95% CI: -0.13, -0.01), P = .02]. No associations emerged for men for any glycaemic marker. HOMA-%B was not associated with brain outcomes in either sex. Women's later-life brain health may be more vulnerable to midlife hyperglycaemia.