Association of waist-calf circumference ratio with incident cognitive impairment in older adults

The longitudinal relation of central fat and muscle mass with cognitive function remains unclear.We aimed to evaluate the relation of anthropometric measures, including BMI, waist circumference (WC), calf circumference (CC), and waist-calf circumference ratio (WCR), with incident cognitive impairment in older adults.A total of 3312 participants aged ≥65 y (mean: 81.8 y) who were free of cognitive impairment [the Chinese version of the Mini-Mental State Examination (MMSE) scores ≥24 points] in the Chinese Longitudinal Healthy Longevity Survey were included. The primary outcome was incident cognitive impairment, defined as MMSE scores <24 points at the exit visit. Secondary outcomes were incident cognitive decline, defined as a reduction of MMSE scores ≥3 points at the exit visit, and incident decline in different cognitive domains, defined as a reduction of MMSE scores in the domain ≥15% at the exit visit.During a median follow-up duration of 3.6 y, 565 (17.1%) participants developed incident cognitive impairment. Overall, with mutual adjustments, higher WC [≥89 cm (fourth quartile) compared with <75 cm (first quartile); adjusted HR: 1.56; 95% CI: 1.19, 2.04] and higher WCR [≥2.9 (fourth quartile) compared with <2.4 (first quartile); adjusted HR: 1.96; 95% CI: 1.52, 2.52] were significantly associated with a higher risk of cognitive impairment, and higher CC [≥34 cm (fourth quartile) compared with <28 cm (first quartile); adjusted HR: 0.44; 95% CI: 0.33, 0.59] was associated with a lower hazard of cognitive impairment. Similar results were found for the secondary outcomes. However, BMI was not significantly associated with the study outcomes.High WC and low CC were significantly associated with higher incident cognitive impairment in older adults. Moreover, WCR had a relatively stronger association with cognitive impairment compared with each circumference, suggesting maintaining both higher lean mass and lower central fat in older adults for the prevention of cognitive impairment.