Eric Bénéfice

Preschool stunting, age at menarche and adolescent height: a longitudinal study in rural Senegal

Objective: To study the impact of preschool stunting on adolescent height and age at menarche in rural West Africa.Design: A longitudinal, population-based study.Setting: The Niakhar study area in Central Senegal.Subjects: 1650 children aged 12–17 y with known height-for-age at the age of 2–5 y.Main outcome measures: Adolescent height; mean age at menarche of girls estimated by the status quo method.Results: The subjects were divided into three groups of preschool height-for-age: <−2, −2 to −1 and >−1 z-score of the NCHS reference. The mean height during adolescence differed significantly according to preschool height-for-age for both boys and girls (P<0.001). Relative risk of adolescent stunting according to preschool stunting varied from 2.0–4.0 depending on age and sex. Estimated mean age at menarche was 17.2 (95% fiducial confidence interval: 16.6–18.7), 16.5 (16.1–17.2) and 15.6 (15.2–16.0) y, respectively, for the three groups of preschool height-for-age (P<0.001). Mean increment from age 5 y to adolescence did not differ significantly among the boys according to preschool stunting, but among the girls aged 16–17 y, the increment was higher for those who had been stunted during preschool life (P<0.01).Conclusion: Some evidence of catch-up growth between the ages of 5 and 17 y was found for stunted girls. The significant delay in sexual maturation of the stunted girls suggests that stunted children of both sexes have a possibility of catch-up growth after the age of 17 y.Sponsorship: The preschool study was supported by the EEC (TSD-036).

Body size, body composition and motor performances of mild-to-moderately undernourished Senegalese children

Relationships between anthropometric dimensions (stature, weight, arm and calf circumferences, and four subcutaneous skinfolds), and motor performances (dash, standing long jump, throw for distance and grip strength) were considered in 348 mild-to-moderately undernourished Senegalese children 5-13 years of age (168 boys and 180 girls). Weights and statures are, on average, below the National Center for Health Statistics (NCHS) reference medians at each age, and deviations are more pronounced in children > 8 years of age and in boys more than girls. Boys, on average, perform better than girls on all tasks. Stature and weight explain about 30-50% of the variance in the performances of children < 10 years of age, while weight explains about 10-25% in children > 10 years of age. Indicators of body composition (estimated arm muscle and subcutaneous fat) have only a limited contribution to the remaining variance in motor performances. Fatness negatively affects the performances of girls > 10 years, but has no effect on performance of boys.

Relationship between stunting in infancy and growth and fat distribution during adolescence in Senegalese girls.

Objective: To study the long-term impact of stunting during infancy on maturation, growth and fat distribution in adolescence.Design: A cohort of 406 Senegalese adolescent girls of rural origin underwent clinical and growth assessments every year from 1995 to 1999.Subjects: Mean coverage rate was 82% at each round. Adolescent girls were 11.4±0.5 y of age in 1995 and 15.5±0.5 y of age in 1999. Their growth status during infancy was known. About 20% of the girls had a height–age (H–age) below −2 Z-scores (chronic malnutrition or stunting) when they were 6–18 months of age. As adolescents, the girls were divided into two groups on the basis of H–age: those stunted and those non-stunted during infancy.Measurements: Sexual maturation was assessed by stage of breast development and menarche. Height, body mass, sitting height, bi-iliac and bi-acromial diameters, and six skinfolds were measured.Results: Differences in sexual maturation between previously stunted and non-stunted girls were not significant. Girls stunted at infancy caught up in body weight and subcutaneous fat mass during puberty, but they did not catch up on stature, sitting height or skeletal breadths (bi-acromial and bi-iliac diameters) until the final observation in 1999. Stunted girls did not have less subcutaneous fat (sum of six skinfolds) or a lower BMI. Regional variation in subcutaneous fat distribution (Z-score profile) indicated greater accretion at the biceps and subscapular sites in stunted compared to the non-stunted girls. Regional fat distribution was also assessed by principal component analysis (PCA) performed on the residuals of the six skinfolds measured during the final round (1999). PCA identified three components. Stunted and non-stunted girls were similar for the first (trunk–extremity contrast) and second (anterior–posterior contrast) components. However, there was a difference for the third component: stunted girls tended to accumulate more subcutaneous fat on the upper part of the body (trunk or arms) than non-stunted girls.Conclusion: Stunted Senegalese girls have a potential for catching up in growth during puberty. The greater accumulation of subcutaneous fat on the upper body in stunted girls may be a consequence of complex hormonal adjustments at the onset of puberty.Sponsorship: Institut de Recherche pour le Développement (IRD anciennement ORSTOM) and the Nestlé Foundation.European Journal of Clinical Nutrition (2001) 55, 50–58

Early nutritional history and motor performance of Senegalese children, 4-6 years of age

The effects of undernutrition on motor coordination and performance of 139 4.0-6.5 year-old Senegalese children were studied. The sample was partitioned into three nutritional history groups: 54 children exposed chronically to a mild-to-moderate form of undernutrition (group A), 52 children hospitalized for severe undernutrition during infancy and nutritionally rehabilitated but who had been subsequently exposed to moderate undernutrition (group B); and 33 children from well-off urban households (group C). Tests included six items from the McCarthy (arm coordination) and the Charlop-Atwell (gross motor coordination) scales, and five motor fitness items (endurance run, shuttle run, distance throw, standing long jump, grip strength). Performances improved with age, and boys performed better than girls in all motor fitness tests except the jump, but not in motor coordination items. In general, group C performed better than group A and B in most of the tests. Body dimensions explained a significant part of variance of motor performance, and stature was the main predictor. After removing the effect of age and body size, differences between nutritional groups disappeared in motor performance, but persisted in certain motor coordination items. It is concluded that chronic undernutrition reflected by reduced body size and perhaps muscle mass is an important determinant of the motor performance of preschool Senegalese children.

Nutritional status, growth and sleep habits among Senegalese adolescent girls

Objective: To study the relation between sleep habits, nutritional status, growth and maturation in a group of African adolescent girls. The main hypothesis to be tested was that sleep length could be an effective way to spare energy, and thus malnourished girls sleep longer than normal girls.Design: Three repeated yearly surveys (1997–1999) on a subsample of girls drawn from a larger study cohort on growth at adolescence.Setting: The Niakhar district in the central part of Senegal.Subjects: In total, 40 girls were initially drawn. Missing girls were replaced at each round by girls having the same characteristics and belonging to the same cohort.Interventions: At each round, data on pubertal development (breast stages and occurrence of menarche), growth and nutritional status were collected. Adolescents wore an accelerometer for three or four consecutive nights and days at each round.Results: At the beginning of the survey, girls were 13.3±0.5 y old. They were under international reference values in weight and height. Their mean sleep duration was 8.5±0.9 h. Their puberty status did not influence their sleep habits; however, they slept more in March than in June, which was related to the seasonal change in daylight. There was a significant relation between body mass index and sleep habits: thinner girls slept a longer time and more quietly than the more corpulent girls.Conclusions: The nutritional status of these girls influenced their sleep habits: this may have been either a direct causal relation or a consequence of a protective attitude on the part of the mothers towards the frailer girls.Sponsorship: The R024 ‘Epidémiologie et Prévention’ of the IRD (France) and the Nestlé Foundation.

Nutritional situation and seasonal variations for pastoralist populations of the Sahel (Senegalese Ferlo)

The nutritional status and food consumption of a population of herders in the Ferlo (Senegal) was studied during a complete seasonal cycle. The Ferlo region is in the Sahelian climatic belt where a long dry season (nine to ten months) alternates with a brief humid season (two to three months). In the existing traditional livestock production system, these climatic variations have an impact first on the living conditions of these people but also on the nutritional status of the herders. Food intakes are insufficient during the rains and one finds a deep nutritional depression during this period; whereas during the dry season, to the contrary, food intake is very good and the nutritional status definitely improves. In an average situation, there is a balance between the losses that occurred during the wet season and the gains at the beginning of the dry season. This balance is nevertheless very precarious. To insure food and nutritional security for the herders, activities must concentrate on seeking solutions

Nutritional status of Amerindian children from the Beni River (lowland Bolivia) as related to environmental, maternal and dietary factors.

OBJECTIVES To report the nutritional status of children aged up to 15 years and their mothers living in a remote Amazonian area of Bolivia, and to study its main social, familial and maternal determinants. SETTING Fifteen Beni River communities located at the foot of the Andes. DESIGN Cross-sectional survey of riverside populations. All childbearing mothers and their children in the 15 communities were examined. METHODS Information on household production, dietary habits and demography was collected. Individual clinical, anthropometric and parasitological examinations were carried out. SUBJECTS A total of 631 persons were examined: 171 mothers and 460 children and adolescents aged 0 to 15 years. RESULTS There were no cases of severe wasting, but 41% of 0-5-year-olds and 36% of 5-10-year-olds were stunted. Among 346 stool specimens examined, 75% were positive for at least one helminth. Diversity of food and quality of diet were satisfactory in 54% of households, but 27% had low diversity scores. Mothers were lighter and shorter than those observed at the national level: 20% had height below 145 cm. Prevalence of anaemia (42%) was also higher. In pre-school children, multivariate analysis indicated a relationship between growth retardation and household factors such as dietary quality, ethnic group and clinical state, but not maternal anthropometry. In contrast, in school-age children and adolescents, growth retardation was related to maternal characteristics. CONCLUSIONS Growth retardation appeared mainly during the weaning period and did not seem to improve thereafter. To ameliorate this situation, an effort should be made to prevent common parasitic and infectious diseases in young children. Follow-up of pregnant mothers during pregnancy and delivery also needs to be reinforced.

Habitual physical activity of Senegalese adolescent girls under different working conditions, as assessed by a questionnaire and movement registration

Summary. Objective: The aim of this study was to measure habitual physical activity in a group of Sereer adolescent females from Senegal. The hypothesis tested was that physical activity levels of adolescent Senegalese girls differ according to location and living conditions and may have a negative impact on growth and nutritional status. Design: Studies of physical activity within the framework of a longitudinal study of growth during puberty. Methods: All the adolescents were born and had been raised in the same rural communities, but some worked as maids in the cities during the dry season (migrants) while the others remained in the villages all year round in order to help their families in daily domestic and agricultural tasks (non-migrants). The study was undertaken in both rural and urban settings on a subsample of 40 migrant and 40 non-migrant girls aged 13.4-15.3, drawn from a cohort of 406 adolescents followed up since 1995. Nutritional status was estimated from anthropometric measurements; sexual maturation was based on stage of breast development and occurrence of menarche. Intensity and patterns of physical activity were derived from movement registration by accelerometry for a 3-day period. The nature and frequency of daily tasks were evaluated by questionnaires. Results: As a whole, the adolescents studied here were smaller, thinner and less mature than girls of the same age from developed countries. Migrants weighed 3.5kg more than nonmigrants and had more muscularity and a thicker fat subcutaneous layer. The day-to-day reliability of accelerometry counts was excellent (intraclass correlation coefficient: 0.90, 95% CI: 0.85-0.93). Mean daily (24h) physical activity counts were higher for migrants than for non-migrants. Migrants spent more time engaged in moderate to heavy activity than did non-migrants (9.3h/24h versus 6.1 h/24h). Non-migrants slept or were inactive for a longer period than migrants (7.6 h/24h versus 6.3h/24h). They also rested for a longer period of the day (2.1h/24h versus 0.8h/24h). When examining the influence of maturational status on physical activity, there was a clear difference between the two groups: the less mature migrants were more active, whereas the reverse was true in villages, where girls at the end of puberty reached higher intensity indices. Conclusions and implications: In both situations, the activity level was high. The nutritional status of migrants was better despite a heavier work load. Differences could be explained by better living conditions and food intake in cities.

Assessment of physical activity among rural Senegalese adolescent girls: Influence of age, sexual maturation, and body composition

PURPOSE To analyze the level of habitual physical activity and its relationship with age, maturational stage, and growth status in a group of adolescent Senegalese girls. METHODS Physical activity was assessed for 3 consecutive years in a sample of 40 girls of rural origin. They were 13.3 +/- 0.5 years old at the beginning of the study and belonged to a Sereer community located in the center of Senegal. Minute-by-minute movement counts using accelerometers enabled quantification of levels of physical activity. The assessment was performed during a 4-day period in the first round (1997) and during a 3-day period in 1998 and 1999. Half of the girls were not yet pubescent during the first round, and the whole sample displayed growth retardation in weight and stature, compared with the World Health Organization/National Center for Health Statistics reference. RESULTS Estimated levels of activity were high, ranging from 1.80 to 1.85 multiples of basal metabolic rate. There was a clear decline in the activity level during the course of study. Schoolgirls were less active than the others. Mature adolescents showed more activity during the night. A weak, but significant and positive correlation existed between body mass index and activity during the day; during the night, there was a positive correlation with fat and lean body mass. CONCLUSION Factors determining the activity level were intricate but greater maturity and better nutritional status appeared to be positively related to the activity level.

Physical activity, cardiorespiratory fitness, motor performance, and growth of senegalese pre-adolescents

Profiles of usual physical activity, cardiorespiratory fitness, motor performance, and growth were measured regularly for 2 years in 40 rural Senegalese (Wolof) children—20 boys and 20 girls—who were 10 or 11 years of age and clinically healthy at the beginning of the study. Compared to National Center for Health Statistics (NCHS) reference data, the children showed lower weight‐for‐age and height‐for‐age throughout the period of observation; the increments of height from year to year were not remarkable and growth spurts were not observed during the study period. The motor performance (running, jumping, throwing) and spirometer test results were inferior to age‐matched American children. When adjusted for actual weight and height, jumping and throwing results were similar to those of American children, but running results remained inferior. Cardiorespiratory function appeared inferior to American children of the same age, although speed of recovery after exertion demonstrated good cardiorespiratory efficiency. Physical activity, directly observed over 2‐day periods on 4 occasions, corresponded to an average energy expenditure of 1.66 Mets (multiples of basal metabolic rate) (boys) and 1.76 Mets (girls), which are close to the FAO/WHO/UNU values for age. The higher energy expenditure of girls could be explained by their participation in domestic tasks. Both boys and girls spent an average of 42 minutes/day on activities equivalent to energy consumption rates equal or greater than 4.8 Mets. Significant correlations existed between the activity index and cardiorespiratory fitness in boys, and between the activity index and motor performances in girls. Physical aptitudes of sampled children appear compatible with the demands of their social and agricultural tasks. However, it appears that persistent malnutrition may have stunted their growth and motor performances.