1.5 Adult Malnutrition
The economic livelihood of populations depends to a large extent on the health and nutrition of adults. In adults, the main cause of a reduction in body weight is a decrease in food intake, often in combination with disease, but when energy intake exceeds energy expenditure, the excess is stored in fat mass. Both underweight and overweight constitute adult malnutrition: once these conditions reach certain levels, the manifestations of adult malnutrition become apparent.
In adults, BMI or body mass index (calculated by dividing weight in kilograms by the square of height in meters) is used to define underweight or overweight. The WHO Expert Committee on Physical Growth has suggested the following classifications: mild underweight (BMI = 17.00-18.49 kg/m2), moderate underweight (BMI = 16.00-16.99 kg/m2), and severe underweight (BMI < 16.00 kg/m2).2 These three groups are considered to be chronically energy deficient (CED). For overweight, the categories are as follows: Grade 1 (BMI = 25.00-29.99 kg/m2), Grade 2 (BMI = 30.00-39.99 kg/m2), and Grade 3 (BMI > 40.00 kg/m2).
There is only a limited literature on assessing nutritional status in adults and on diagnosing and treating malnourished adults. However, important health effects have been shown for those with BMI values below 18.5 kg/m2 and for those above 25 kg/m2. Adults with low body weight allocate fewer days to heavy labour and are more likely to fail to appear for work owing to illness or exhaustion.76 There seems to be a continuous gradient in work capacity and productivity that is linked to body weight. In developing countries there is some evidence that individuals with a BMI below 18.5 kg/m2 show a progressive increase in mortality rates as well as increased risk of illness. A recent study among Nigerian men and women has shown that mortality rates among CED individuals who are mildly, moderately, and severely underweight are 40%, 140%, and 150% greater respectively than rates among non-CED individuals.2, 77
Mid-upper-arm circumference (MUAC) has recently emerged in the literature as a potential screening tool for poor nutritional status in adults. MUAC has been analyzed in adults, and cut-offs have been calculated equivalent to BMI cut-offs for chronic energy deficiency using a range of data sets from developing countries.78
At the other end of the spectrum, overweight is associated with an increased prevalence of cardiovascular risk factors such as hypertension, unfavourable blood lipid concentrations, and diabetes mellitus.79 It is also a major risk factor for the development of gallstones and is related to osteoarthritis in several joints. Overweight and the risk of endometrial cancer increase in direct proportion.80 Mortality for both men and women is raised among individuals with a high BMI.81
A series of studies provides a basis for understanding the dynamic shifts in body composition that have occurred among adults in recent decades. There is now ample documentation that in Latin America, North Africa and the Middle East, and South-East Asia, more overweight than underweight exists among adults.82, 83 The CED: obesity ratio, which reflects the ratio of undernutrition to overnutrition in a population, has shifted dramatically in the past several decades in many countries.82 Research from Latin America has shown that the burden of obesity is becoming greater among the poor than among the higher-income groups.84
Further studies have used available national surveys from 1982 to 1996 from Latin American countries to estimate the prevalence of overweight in women 15 to 49 years old, as well as exploring recent trends.38 A high level of overweight (a prevalence of 34 - 49%, excluding Haiti) was found in eight Latin American countries. Trends in obesity for Brazil, the Dominican Republic, and Peru also showed an increase. As for age distribution, studies in Brazil and elsewhere show that obesity is higher among 40 - to 50-year-olds than among younger adults. However, obesity rates then begin to decrease with advancing years in most populations.
For this report we have brought together the data for nonpregnant women 20 to 49 years old, from the latest available Demographic and Health Surveys85 and three national nutrition surveys.38 Similar national survey data are not available for men. Data from 16 countries in Africa, 10 countries in Latin America and the Caribbean, 3 countries in Asia, and 1 country in North America are presented (Table 1.8).
TABLE 1.8: Prevalence of underweight and overweight of women 20-49 years old by country
Underweight is common among women in developing countries. Judging from survey results from South Central Asia, underweight is widespread among women in this sub-region. Some 51.3% of women in Bangladesh are underweight, about half of whom are moderately or severely underweight, with a BMI below 16.99 kg/m2. In six countries surveyed in Africa mild underweight affects more than 10% of women, and in two countries (Chad and Madagascar) prevalences are greater than 15%. In five countries surveyed in Africa moderate and severe underweight affects more than 3% of women. Except for Haiti, underweight among women in Latin America is less common. For most countries surveyed in this region, prevalences of mild underweight are well below 10%, and moderate combined with severe underweight affects less than 3% of women. Overweight (Grade 1) is seen in about one-third of women in Peru (36.6%), Bolivia (36.1%), and Colombia (31.6%) and affects at least one in four women in all countries surveyed, except for Haiti. Overweight prevalence rates exceed 15% in two African countries, Comoros and Namibia. Nearly one-third of Egyptian women have Grade 1 overweight.
[Ukrainian] [English] [Russian]