A cross-sectional association between higher physical activity (PA) and larger hippocampi is already detectable by middle age for patients with type 1 diabetes (T1D), and it appears robust to chronic hyperglycemia and insulin sensitivity, a recent study found. Researchers analyzed neuroimaging and self-reported PA data from 79 adults with T1D from the Pittsburgh Epidemiology of Diabetes Complications Study (mean age 50 years, mean duration 41 years) and 122 similarly aged adults without T1D (mean age 48 years). They found:

• PA was significantly lower in the T1D than in the non-T1D group (median [interquartile range] 952 kcal [420–2,044] vs 1,614 kcal [588–3,091], respectively).
• Higher PA was significantly associated with larger hippocampi for T1D, but not for non-T1D.
• Neither hyperglycemia nor glucose disposal rate substantially modified this association.
• Relationships between PA and total brain gray matter volume were similar.