Determinants of further survival in centenarians from the province of Mantova

The MALVA project, one of the first Italian studies on population-based samples of centenarians, was addressed to the subjects aged 98+ residing in the province of Mantova (Northern Italy) at the 1st April 1998. The present study aims at analyzing the impact of selected clinical and socio-demographic variables on further survival of the 77 participants in the MALVA study. Adopting methods for multiple imputation of missing value, four distinct Cox regression models were estimated using groups of predefined variables describing socio-demographic characteristics, functional status, nutritional status, cardiovascular risk factors. Each model was adjusted for the effects of gender and age. Finally two complete models have been considered : the first one including the statistically significant variables in the previous analysis, and the second one obtained with a backward selection procedure. The variables included in the final models can be seen as markers of "frailty" or correlated conditions. Most of these variables maintained a significant influence on survival, however belonging to the "underweight" BMI category and being institutionalized emerged as the best "frailty" indicators in the centenarians from the province of Mantova. The results of this study are in agreement with several previous studies in recognizing that factors predicting mortality in centenarians are not the same well-known predictors of mortality in the middle-aged and younger elderly.