The enigma of increased non‐cancer mortality after weight loss in healthy men who are overweight or obese

Abstract

The relative risk (RR; 95% CI) for non-cancer mortality during follow-up was higher in men with decreasing BMI in all subgroups: RR 2.64 (1.46-4.71, baseline BMI <21 kg m(-2)), 1.39 (0.98-1.95, baseline BMI 22-25 kg m(-2)), and 1.71 (1.18-2.47, baseline BMI 26+ kg m(-2)), using BMI-stable men as reference group. Correspondingly, the non-cancer mortality was also higher in men with increasing BMI, but only in the obese group (baseline BMI 26+ kg m(-2)) with RR 1.86 (1.31-2.65). In a subanalysis, nonsmoking obese (30+ kg m(-2)) men with decreased BMI had an increased non-cancer mortality compared with BMI-stable obese men (Fischer's test: P=0.001). The mortality risk for nonsmoking overweight men who increased their BMI compared with BMI-stable men was also significant (P=0.006), but not in corresponding obese men (P=0.094). CONCLUSIONS. Weight loss in self-reported healthy but overweight middle-aged men, without serious disease, is associated with an increased non-cancer mortality, which seems even more pronounced in obese, nonsmoking men, as compared with corresponding but weight-stable men. The explanation for these observational findings is still enigmatic but could hypothetically be because of premature ageing effects causing so-called weight loss of involution.