BMI and mortality in nursing home

N Veronese, E Cereda, M Solmi, S A Fowler, E Manzato, S Maggi, P Manu, E Abe, K Hayashi, J P Allard, B M Arendt, A Beck, M Chan, Y J P Audrey, W-Y Lin, H-S Hsu, C-C Lin, R Diekmann, S Kimyagarov, M Miller, I D Cameron, K H Pitkälä, J Lee, J Woo, K Nakamura, D Smiley, G Umpierrez, M Rondanelli, M Sund-Levander, L Valentini, K Schindler, J Törmä, S Volpato, G Zuliani, M Wong, K Lok, J M Kane, G Sergi, C U Correll

Body mass index (BMI) and mortality in old adults from the general population have been related in a U-shaped or J-shaped curve. However, limited information is available for elderly nursing home populations, particularly about specific cause of death. A systematic PubMed/EMBASE/CINAHL/SCOPUS search until 31 May 2014 without language restrictions was conducted. As no published study reported mortality in standard BMI groups (<18.5, 18.5-24.9, 25-29.9, ≥30 kg/m(2) ), the most adjusted hazard ratios (HRs) according to a pre-defined list of covariates were obtained from authors and pooled by random-effect model across each BMI category. Out of 342 hits, 20 studies including 19,538 older nursing home residents with 5,223 deaths during a median of 2 years of follow-up were meta-analysed. Compared with normal weight, all-cause mortality HRs were 1.41 (95% CI = 1.26-1.58) for underweight, 0.85 (95% CI = 0.73-0.99) for overweight and 0.74 (95% CI = 0.57-0.96) for obesity. Underweight was a risk factor for higher mortality caused by infections (HR = 1.65 [95% CI = 1.13-2.40]). RR results corroborated primary HR results, with additionally lower infection-related mortality in overweight and obese than in normal-weight individuals. Like in the general population, underweight is a risk factor for mortality in old nursing home residents. However, uniquely, not only overweight but also obesity is protective, which has relevant nutritional goal implications in this population/setting.