Malawi maternal and child nutrition study: Study design and anthropometric characteristics of children and adults

The Validity of Clinic-Based Nutrition Surveillance Data: A Study from Selected Sites in Northern Malawi

Many developing countries collect on the weight for age of children attending health facilities as one element of a nutrition surveillance system. This study compares the estimates of malnutrition from seven health clinics in northern Malawi with estimates derived from nearby community-level surveys. The results show that prevalence of underweight in clinics does not accurately reflect community prevalence. Clinic estimates often differ by two- to threefold from community estimates, and the direction of the bias is not constant across clinics, making these data an invalid basis for targeting programmes according to nutritional need. Similar results were reported in five other studies in the literature, indicating that the Malawi results are not unusual. It is suggested that, contrary to current practice, cross-sectional clinic-based data should be assumed invalid for targeting purposes unless proved otherwise in a given country. Trend data at regional and country levels require further validation.

Impact of Maternal Household Decision-Making Autonomy on Child Nutritional Status in Bangladesh

This study examines the relationship between maternal household decision-making autonomy and children’s nutritional status using data from 2011 Bangladesh Demographic and Health Survey. The analyses are restricted to 2056 currently married, nonpregnant women aged 15 to 49 years who had at least 1 birth 5 years preceding the survey. Theoretically relevant predictors of children’s nutritional status including maternal autonomy are analyzed to identify factors significantly associated with children’s nutritional status using stepwise logistic regression. Results indicate that 34.8% children are stunted, 16.1% are wasted, and 45.9% children are underweight. Children whose mothers participated in making all household decisions are 15%, 16%, and 32% significantly less likely to be stunted (odds ratio = 0.85; 95% CI = 0.67-0.98), underweight (odds ratio = 0.84; 95% CI = 0.70-0.98), and wasted (odds ratio = 0.68; 95% CI = 0.52-0.90), respectively, than mothers who did not participate in making any decision. Increasing maternal decision-making autonomy may reduce the prevalence of malnourished children as well as contribute to have a healthier future generation.

Food and nutrition policy: a biological anthropologist's experiences from an academic platform

OBJECTIVES

Biological anthropologists within academia and in other sectors are increasingly engaged in a variety of problem-oriented research and in the design, implementation, or evaluation of policies and programs, domestically and abroad. Such work can have distinctive requirements in terms of disciplinary background, professional orientation, and professional development. This article explores these issues through the author's autobiographical account of a career in food and nutrition policy from within an academic nutrition department.

METHODS

The article is guided by an analytical framework that compares eight projects in terms of their mode of knowledge production, academic impact, public impacts, and personal rewards. The projects range from village-based surveys in Samoa and Malawi to food security planning in upstate New York communities, US policies on genetically engineered (GE) foods, and participant-observer research on nutrition policy development in low-income countries.

RESULTS AND CONCLUSIONS

The cumulative experience reveals the importance of a commitment to problem-solving, a transdisciplinary orientation, intellectual and methodological dexterity, ongoing engagement with policy actors and openness to emergent research questions, new research settings, and nontraditional funding sources.

Ecogeographical associations between climate and human body composition: analyses based on anthropometry and skinfolds

In the 19th century, two "ecogeographical rules" were proposed hypothesizing associations of climate with mammalian body size and proportions. Data on human body weight and relative leg length support these rules; however, it is unknown whether such associations are attributable to lean tissue (the heat-producing component) or fat (energy stores). Data on weight, height, and two skinfold thickness were obtained from the literature for 137 nonindustrialized populations, providing 145 male and 115 female individual samples. A variety of indices of adiposity and lean mass were analyzed. Preliminary analyses indicated secular increases in skinfolds in men but not women, and associations of age and height with lean mass in both sexes. Decreasing annual temperature was associated with increasing body mass index (BMI), and increasing triceps but not subscapular skinfold. After adjusting for skinfolds, decreasing temperature remained associated with increasing BMI. These results indicate that colder environments favor both greater peripheral energy stores, and greater lean mass. Contrasting results for triceps and subscapular skinfolds might be due to adaptive strategies either constraining central adiposity in cold environments to reduce cardiovascular risk, or favoring central adiposity in warmer environments to maintain energetic support of the immune system. Polynesian populations were analyzed separately and contradicted all of the climate trends, indicating support for the hypothesis that they are cold-adapted despite occupying a tropical region. It is unclear whether such associations emerge through natural selection or through trans-generational and life-course plasticity. These findings nevertheless aid understanding of the wide variability in human physique and adiposity.

Short ReportRelationship between arm span and stature in Malawian adults

OBJECTIVE

The aim of this cross-sectional study was to assess the relationship between height and arm span in adult Malawians.

SUBJECTS AND METHODS

142 males and 128 females between the ages 20 and 76 years were recruited from among the patients attending various clinics at Queen Elizabeth Central Hospital, Blantyre, Malawi. All subjects were free from physical deformities. The anthropometric measurements included standing height and arm span.

RESULTS

The arm span exceeded height in all age groups of males and females. The mean difference between the height and arm span values for females was 9.9 +/- 4.9 cm (t = 16.28, p<0.001) and for males was 11.6 +/- 4.4 cm (t = 14.74, p<0.001). The gender difference between height and arm span measurements was statistically significant (t = 9.58, p<0.001 and t = 10.24, p<0.001, respectively). Correlation of arm span and height for males was 0.871 and for females was 0.815. Prediction equations were derived from regression analysis. RSD values were 8.709 and 6.914 for equations for males and females, respectively.

CONCLUSIONS

Stature of Malawian adults can be estimated from arm span measurements using regression equations.

Anthropometric indices in rural Malawians aged 45–75 years

OBJECTIVE

The aim of this cross-sectional study was to assess anthropometric parameters of rural people aged 45-75 years in the Southern Region of Malawi.

SUBJECTS

97 males and 101 females aged 45-75 years were selected from 10 villages in Balaka district using a stratified cluster sampling method. Most responders were small-scale farmers growing maize and vegetables for household consumption. The anthropometric measurements taken were height, weight, triceps skinfold (TSK) and mid-upper arm circumference (MUAC). The derivatives from anthropometric measurements included body mass index (BMI), mid-upper arm muscle area (MUAMA) and mid-upper arm fat area (MUAFA). Weight status of Malawian subjects was estimated using WHO (1995) categories for BMI values, and height, weight, TSK, MUAC, MUAMA and MUAFA were compared with NHANES reference data for black sample.

RESULTS

Correlation between age of subjects and the anthropometric indices was weak and insignificant. Males were generally taller and lighter than females. All anthropometric indices of Malawian subjects were considerably lower than NHANES medians. However the mean values of height, weight, MUAC and MUAMA of females were closer to the reference values than those of males. It was found that 9.1% of Malawian subjects had mild thinness (BMI 17.0-18.4 kg m(-2)), 13.6% had moderate thinness (BMI 16.0-16.9 kg m(-2)) and 18.2% exhibited severe thinness (BMI<16.0 kg m(-2)). The proportion of thin persons was higher (chi2 = 9.58, n = 1, p<0.01) among males than females (50.0% versus 35.7%).

CONCLUSIONS

This study indicates that undernutrition is a serious problem among rural Malawians aged 45-75 years.

Growth of urban school children in Malawi

The objective of this cross-sectional study was to assess growth pattern of urban school children in Malawi from low socio-economic strata and to compare anthropometric measurements of the children to data from the region of South-Central Africa and to international standards. A total of 493 urban school children aged 6-17 years were selected randomly from two primary schools in semi-urban Blantyre, the largest city in Malawi. Anthropometric measurements included height, weight, mid-upper arm circumference, triceps skinfold thickness, mid-upper arm muscle circumference and maximal grip strength of the stronger hand. All parameters of Malawian children of both sexes were lower than medians of WHO/NCHS reference data. Expressed as percentage of WHO/NCHS references, the relative means of height, weight, mid-upper arm circumference and mid-upper arm muscle circumference of Malawian girls were considerably higher than those of boys, and older girls had better parameters than younger ones. Older pupils of both sexes had higher triceps skinfold thickness relative to the international references than the younger children. Mean maximal grip strength values of boys and girls were not significantly different. For girls, the relative values increased with age, while for boys they decreased. It is concluded that younger primary school pupils have similar body sizes to their counterparts from the region. Adolescents, particularly girls, have more favourable anthropometric parameters which approach WHO/NCHS reference data.

The timing hypothesis and body proportionality of the intra-uterine growth retarded infant

Intra-uterine growth retardation (IUGR) is a heterogeneous designation, as seen in the fact that neonatal morbidity and mortality differ for IUGR infants that are disproportionate vs proportionate based on the ponderal index (weight/height(3)). Much less is known, however, concerning the etiology of these two forms. This study tests the hypothesis that the form of IUGR (proportionate vs disproportionate) is related to the timing of stress during gestation, specifically, that linear growth is compromised by second trimester stress and the ponderal index is compromised by third trimester stress. This hypothesis is tested using data on 755 full-term mother-infant pairs studied prospectively in rural northern Malawi where the seasonal stress of the pre-harvest rainy season (PHRS) is a regular occurrence. The results indicate that exposure to PHRS in the second trimester is not associated with weight, length, or the ponderal index at birth. Exposure to PHRS in the third trimester is associated with diminished birth weight and length, but not ponderal index. The results do not support the timing hypothesis, at least as previously framed in the literature, and suggest the possibility that linear growth may precede or be more sensitive to prenatal stress than the ponderal index. Am. J. Hum. Biol. 11:638-646, 1999. Copyright 1999 Wiley-Liss, Inc.

The timing of maternal weight gain during pregnancy and fetal growth

The morbidity, mortality, and growth patterns of intrauterine growth retarded (IUGR) infants vary according to body proportionality, or the ponderal index. Much less in known, however, about the factors that give rise to the various forms of IUGR. This study tests that hypothesis that the rate of maternal weight gain during early/mid and late pregnancy are differentially related to body size and proportions at birth in a nutritionally stressed population in rural Malawi. The data consist of prospectively collected measurements of maternal weight and infant size at birth on 272 mother-infant pairs. The results reveal that early/mid and late weight gain are both related to birth weight and length, but not to the ponderal index. Late weight gain is particularly predictive of infant size among thin women (BMI </= 18.5) and is several times stronger than early/mid weight gain. These findings do not support the timing hypothesis as previously stated in the literature, but do add to the suggestions arising from a disparate literature that growth acceleration in length may precede acceleration in weight-for-length during a period of nutritional replection in phases of the life cycle characterized by rapid growth. Am. J. Hum. Biol. 11:627-637, 1999. Copyright 1999 Wiley-Liss, Inc.

Growth patterns among seminomadic pastoralists (Datoga) of Tanzania

Anthropometric measurements made on 470 individual children (age 0-18 years) from a seminomadic population of Datoga pastoralists living in northern Tanzania were used to describe patterns of child growth. Comparisons with reference growth curves derived from American samples suggest that pastoral Datoga children grow poorly in this region. Body compositional changes with age differed markedly from the reference population. There were negligible fat gains through childhood, even among females. Comparison with data on other East African pastoralists showed that population growth performance is intermediate between that of nomadic and settled pastoralists. Little catch-up growth occurs during childhood, and adolescence appears to be delayed among males. The results contribute to the growing database on health indicators for African pastoralists and suggest a need for further research to investigate mechanisms for growth stunting in these populations.

Climatic influences on human body size and proportions: ecological adaptations and secular trends

This study reevaluates the long-standing observation that human morphology varies with climate. Data on body mass, the body mass index [BMI; mass (kg)/stature (m)2], the surface area/body mass ratio, and relative sitting height (RSH; sitting height/stature) were obtained for 223 male samples and 195 female samples derived from studies published since D.F. Roberts' landmark paper "Body weight, race, and climate" in 1953 (Am. J. Phys. Anthropol. 11:533-558). Current analyses indicate that body mass varies inversely with mean annual temperature in males (r=-0.27, P < 0.001) and females (r=-0.28, P < 0.001), as does the BMI (males: r=-0.22, P=0.001; females: r=-0.30, P < 0.001). The surface area/body mass ratio is positively correlated with temperature in both sexes (males: r=0.29, P < 0.001; females: r=0.34, P < 0.001), whereas the relationship between RSH and temperature is negative (males: r=-0.37, P < 0.001; females: r=-0.46, P < 0.001). These results are consistent with previous work showing that humans follow the ecological rules of Bergmann and Allen. However, the slope of the best-fit regressions between measures of body mass (i.e., mass, BMI, and surface area/mass) and temperature are more modest than those presented by Roberts. These differences appear to be attributable to secular trends in mass, particularly among tropical populations. Body mass and the BMI have increased over the last 40 years, whereas the surface area/body mass ratio has decreased. These findings indicate that, although climatic factors continue to be significant correlates of world-wide variation in human body size and morphology, differential changes in nutrition among tropical, developing world populations have moderated their influence.