Body mass index, lifestyles, physical performance and cognitive decline : the "Treviso Longeva (Trelong)" study

OBJECTIVES: The relative contributions of risk factors, as body mass index (BMI), depression, chronic diseases, smoking, and lifestyles (as physical and performance activity, social contacts and reading habit) to cognitive decline in the elderly are unclear. We explored these variables in relation to 7-year cognitive decline in long-lived Italian elderly. DESIGN: Secondary data analysis of a longitudinal study of a representative, age-stratified, population sample. SETTING: The TREVISO LONGEVA (TRELONG) Study, in Treviso, Italy. PARTICIPANTS: 120 men and 189 women, age 77 years and older (mean age 80.2 ± 6.9 years) survivors after seven years of follow up. MEASUREMENTS: Cognitive decline measured as difference between Mini-Mental State Examination (MMSE) score in 2003 and in 2010; Body mass index (BMI), handgrip, Short Physical Performance Battery (SPPB) score, social contacts, reading habit, sight, hearing, schooling, mediterranean diet and multiple clinical and survey data recorded at baseline in 2003. RESULTS: In separate univariate analyses, age, SPPB score < 5, depressive symptoms (GDS) and more comorbidities (CCI) were associated with greater cognitive decline. Otherwise higher BMI, higher handgrip, reading habit, non-deteriorated sight and hearing, and schooling were protective. In a final multivariate model, age and higher BMI were associated with greater cognitive decline while reading habits was protective. SPPB score < 5 tends, though weakly, to be associated with greater cognitive decline. These associations remained with multivariate adjustment for gender, schooling, Charlson co-morbidity index (CCI) and baseline MMSE. CONCLUSION: Age and higher baseline BMI, independent of gender, and other confounding factors, are risk factors for cognitive decline. Reading habit plays a protective role seven years later among northern Italian adults aged 70 years or older. Low physical performance tends, though weakly, to be associated with greater cognitive decline.