Overweight elderly patients have elevated CVD- and stroke-related but not all-cause mortality risk
Elderly overweight individuals have an elevated risk of death due to cardiovascular disease (CVD) and stroke but not all-cause mortality, according to findings from the SLAS* cohort.
Individuals aged ≥65 years who were overweight or obese (BMI ≥30 kg/m2) had an elevated risk of CVD- and stroke-related mortality (hazard ratio [HR], 10.0; p=0.0086), though not of all-cause mortality (hazard ratio [HR], 0.98–1.29). [PLoS One 2017;12:e0180818]
Conversely, individuals aged ≥65 years who were underweight (BMI <18.5 kg/m2) had an increased risk of both all-cause (HR, 1.78; p=0.0336) and CVD- and stroke-related mortality (HR, 6.15; p=0.0299).
Among individuals aged 55–64 years, all-cause mortality risk was increased in those who were underweight (HR, 4.92; p<0.0138), of normal weight I (BMI 18.5–22.9 kg/m2, HR, 3.41; p=0.0149), and overweight or obese (HR, 4.05; p=0.0423) compared with individuals with a BMI of 23–24.9 kg/m2 (normal weight II).
Individuals with a BMI of 23–24.99 kg/m2 had the lowest risk of all-cause and CVD- and stroke-related mortality, regardless of age.
Despite the results, the researchers advised caution when interpreting the findings to determine the optimal BMI in elderly patients.
“[I]t should not be interpreted to mean that obesity conveys a lower mortality risk in older persons compared with younger and middle-aged persons … the absolute mortality risk associated with increased BMI is still higher in older persons because of the marked increase in mortality with advancing age,” they said.
Furthermore, the small number of stroke- and CVD-related deaths may have skewed the results towards an association with obesity.
“[T]he lack of association of overweight-obesity with increased total mortality among the older participants was due to lower mortality predominantly from nonvascular causes of death,” they said.
“[O]lder persons tend to have more body fat at the same BMI as younger adults, with greater BMI possibly reflecting greater fat-free mass, rather than greater body fat,” said the researchers, on the drawback of using BMI as a measure of body fat, and suggested that future research incorporate other measures of body composition to elucidate these findings.
Study participants were 2,604 individuals of Chinese ethnicity aged ≥55 years from the SLAS cohort who were followed up from 2003 to 2011. Of these, 6.1 percent were underweight and 4.6 percent were overweight-obese class I, II, and III (BMI ≥30 kg/m2). There were 224 deaths, 17 percent (n=38) of which were due to CVD and stroke.