The prevalence of obesity in human populations increased markedly in the last four decades of the second millennium. On average, body weight increases throughout adult life up to the age of about 60 years. Most of the increase in weight with aging is due to fat accumulation in several depots in the body. After the age of 60, average
Handbook of Models for Human Aging
Copyright © 2006 by Academic Press All rights of reproduction in any form reserved.
body weight begins to decline and by the age of 80 the prevalence of obesity is only about a third of that at age 60. The factors responsible for the decline in body weight with age are complex and incompletely understood. They include loss of muscle (sarcopenia), due in part to decreased activity and the endocrine changes that accompany aging. There is also an element of selection since obesity increases risk of conditions, including cardiovascular diseases and cancer, which shorten life. Furthermore, there is a well-established association between calorie restriction and longevity. Influences on the body weight of aging cohorts are multiple and need to be documented better.
Increased prevalence of obesity in the past 50 years has arisen because of increased calorie intake in the face of declining levels of physical activity. Decreased physical activity with aging may relate to changes in body composition (loss of muscle) and limitations imposed by diseases such as arthritis and vascular disorders. The link between obesity and ill health and risk, particularly of vascular disorders, has been long recognized and amply documented in a large number of recent studies. Awareness of the risks of obesity has increased, leading to development of a range of public health or treatment interventions to either prevent or treat the condition. In spite of these, available evidence suggests that the prevalence of obesity is still increasing. Mokdad et al. (2003) conducted a survey of over 195,000 adults in the United States in 2001. Compared with the preceding year, the prevalence of obesity had increased from 19.85 to 20.9%, an increase of 5.6%. Diabetes prevalence increased from 7.3 to 7.8% of the population, an increase of 8.2%. Diabetes and cardiovascular risk factors were much more common in obese individuals. Recent studies from Spain and Canada also confirm increases in obesity in the elderly, with up to 40% of the population affected. Even in societies where obesity has traditionally been less common, such as Japan, an increasing proportion of the elderly population is either overweight or obese. At all ages, including the elderly, obesity is more common in women than in men. For this reason, the relative protection that women have enjoyed against vascular disorders is being lost.
The relationship between obesity and socioeconomic status is also changing: Zhang and Wang (2004) have studied the link between educational attainment (as a surrogate marker for social status) and obesity in four cohorts of the National Health and Nutrition Examination Surveys (NHANES) between 1971 and 2000. There has been a progressive diminution in the excess of obesity in low socioeconomic groups. A recent study from Finland (Sulander et al., 2004) has confirmed the rising prevalence of obesity among the elderly, and also that this increase is not as markedly related to socioeconomic status as would have been expected 10 years ago. Obesity is still a disorder associated with poverty and poor education, but it is also a disease of affluence.
Recent studies also suggest that improved survival among institutionalized elders and those with special needs such as severe learning difficulties might also be contributing to the increased prevalence of weight problems in the elderly. Projections of the likely rise in obesity prevalence have been based on a combination of surveys (Arterburn et al., 2004). It is estimated that the proportion of those aged 60 years and over who are obese will increase from 32.0% in 2000 to 37.4% in 2010. In the United States, this means an increase in the number of elderly obese subjects from 14.6 million to 20.9 million. Correspondingly, it is estimated that, over the next decade, the proportion of subjects aged 60 and over who are in the range of weight regarded as ideal will decrease from 30.6 to 26.7%.
Was this article helpful?