Читать книгу Pathy's Principles and Practice of Geriatric Medicine - Группа авторов - Страница 390

On the other hand, little is known about the effect of intentional weight loss driven by health carers on mortality in older adults. A randomised control trial showed no difference in mortality between those who lost a mean of 4.4 kg of body weight in comparison with the other group.²⁹

However, mortality is only a small part of the substantial burden of disease caused by obesity‐related conditions such as hypertension, diabetes mellitus, coronary artery disease, degenerative arthritis, and cancers of the breast, uterus, and colon. Short‐term reductions in caloric intake (dieting) have favourable effects on blood pressure, cholesterol, and metabolic rate. These benefits require at least a 20% reduction in caloric intake.

Weight loss has been shown to reduce disease‐specific risks such as hypertension and type 2 diabetes. A sample of older and overweight obese subjects from several randomized control trials (RCTs) of weight loss programs with caloric restriction and exercise or exercise alone were contacted 2.2–5.8 years after RCT termination.³⁰ Weight loss was higher in the caloric restriction group than in the exercise group and maintained in both groups in the long term. The decrease in fat mass and lean body mass was higher in the caloric‐restriction group, but in the long term, no difference in physical performance was shown between interventions.

The Look AHEAD RCT in adults with diabetes compared intensive lifestyle intervention and diabetes care support. Weight loss, improvement in fitness, and other cardiovascular risk factors were maintained in the long term in the lifestyle intervention group.³¹ However, objective neuropathy signs were not different across the groups,³² and marginally greater cognitive decline was shown with lifestyle intervention in obese subjects during a five‐year follow‐up.³³ Despite the reduction in cardiovascular disease risk factors with intensive lifestyle intervention, no reduction in cardiovascular events was shown.³⁴

However, it should be noted that overweight/obesity‐related comorbidities, particularly those associated with insulin resistance syndrome (e.g. hypertension, dyslipidaemia, and hyperinsulinemia) can be improved independently of weight loss.^35,36 Blood pressure can be lowered in the absence of weight loss by dietary changes.³⁷ The effect on blood pressure from non‐pharmacological interventions can be maintained for three to five years despite significant increases in body weight.³⁸ Other trials of coronary artery disease have shown prevention effects to be independent of weight loss. Finally, improvement in physical function can also be obtained without weight loss.³⁹ The data suggest that improvements in comorbid conditions can be enhanced with lifestyle changes but that the effect is independent of whether weight loss occurs.