The aim of this study was to investigate the relationship between body mass index (BMI) categories and comorbidity in 9067 patients (age range 18‒94 years) who underwent upper digestive endoscopy in Northern Sardinia, Italy. The majority of participants (62.2%) had a BMI under 25 kg/m2, overweight was detected in 30.4%, and obesity (BMI ≥ 30 kg/m2) in 7.4% of patients. The most frequent illness recorded was hypertension followed by cardiovascular and liver disease. The multivariate analysis, after adjusting for sex, residence, marital status, smoking habits, occupation and hospitalization detected an association between comorbidity and aging that was statistically significant and progressive. Among patients younger than 60 years (n = 5612) the comorbidity risk was higher for BMI ranging 27.5‒29.9 kg/m2 compared with BMI 25.0‒27.4 kg/m2 (RR = 1.38; 95% CI 1.27‒1.50 vs. RR = 0.86; 95% CI 0.81‒0.90). In patients older than 60 years (n= 3455) the risk was lower for a BMI in the range 27.5-29.9 kg/m2 compared with a BMI in the range 25.0-27.4 kg/m2 (RR = 1.11; 95% CI 1.05‒1.18 vs. RR = 1.28; 95% CI 1.21‒1.35). These results suggest that being moderately overweight is a marker of a healthy aging process and might protect, at least in part, against comorbidity. However, further research is needed to better understand this unexpected finding.
Keywords: Body height; Sardinia; comorbidity.