Physical growth of infants 7 to 13 months of age: results from a national survey

This study considers measurements of weight, recumbent length, head circumference, triceps skinfold, and arm circumference of 1,100 infants aged 7 to 13 months from a cross-sectional sample representative of the U.S. infant population. Based on these data, smoothed percentiles of weight, recumbent length, head circumference, triceps skinfold, and arm circumference by sex and age (in months) and weight for recumbent length were calculated. Compared with the percentile values from the National Center for Health Statistics (NCHS; Hamill et al., 1977, DHEW Publ. No. PHS 78-1650), percentile values from the 1984 Ross Laboratories Infant Nutrition Survey (RNS) for weight, recumbent length, and weight for recumbent length tended to be smaller (p less than .05). We attribute these variations to differences in sampling design and conclude that they are not of sufficient magnitude to warrant new growth charts. Smoothed percentiles for triceps skinfold and arm circumference presented herein are new reference values that can be used for assessment of the nutritional and growth status of older infants.     

A Comparison of Health Complaints of Settled and Nomadic Turkana Men

This article examines the health complaints of settled and nomadic Ngisonyoka Turkana of northwest Kenya. Samples of 152 nomadic and 124 settled men, aged 14 and over, were surveyed about their health status. The general pattern of disease reported concurs with previous studies of health among Turkana; that is, the primary complaints are respiratory tract infections and eye infections. The settled Turkana reported more severe complaints and higher rates of infectious disease than the nomads, including a significantly higher frequency of cold with cough, eye infection, and chest infection. Although the settled males as a group had slightly higher body mass index and other measures of body fat than the nomadic group, none of these indicators of body composition were predictive of health complaints. Observed differences in health patterns are possibly related to differences in dietary composition, exposure to pathogens associated with population density and environmental pollution, physical activity patterns, and psychosocial stress.     

Pregnancy outcome for nomadic Turkana pastoralists of Kenya

The outcome of an individual pregnancy is a key component of overall reproductive success and is strongly influenced by environmental, behavioral, and biological variation within populations. This prospective study examined the outcomes of 68 pregnancies among nomadic Turkana of Kenya from July 1993 to July 1994. A total of 12 women experienced pregnancy losses, and 3 women experienced live births with a subsequent perinatal death. The following characteristics are associated with increased risk for experiencing a fetal or perinatal death: severe morbidity episodes, shorter nonpregnant intervals, lower third-trimester weight, higher third-trimester summed skinfolds but limited third-trimester reduction in summed skinfolds, and higher activity levels late in gestation. Turkana newborns measured within 48 hr of birth (n = 19) weighed an average of 2,860 +/- 640 g and had a mean ponderal index of 2.72 +/- 0.46. Variation in birth weight was predicted by preterm delivery, delivery during the wet season, and maternal morbidity levels. Birth length averaged 50.8 +/- 6.8 cm and was positively influenced by full term delivery, better maternal health, and birth during the dry season. These results suggest complicated pathways linking the physical environment, subsistence requirements, heterogeneity in maternal fitness, behavior, and pregnancy outcome. The results augment the larger picture of reproductive success for Turkana nomads who live in a highly variable savanna environment.     

Pubertal timing, hormones, and body composition among adolescent Turkana males

The Turkana, like other East African pastoral groups, are known for their tall adult stature, achieved despite a blunted growth spurt during adolescence and continued growth into the early 20s. To investigate the hormonal mechanisms associated with the pattern of slow and continued adolescent growth, we collected data on hormonal status, height, weight, and trunk skinfolds and ethnographic self-reports of testicular maturation in a cross-sectional sample of 35 nomadic and 37 settled Turkana males aged 14-24. Hormonal determinations included testosterone (T), sex hormone-binding globulin (SHBG), and dehydroepiandrosterone (DHEA) in blood, in addition to urinary DHEA. Self-reports of testicular maturation showed no difference between settled and nomadic subpopulations. However, nomadic boys exhibited significantly higher levels of T, DHEA, and SHBG. Of all the hormones, only SHBG showed a significant relationship with age. Multiple regression models show blood T and SHBG to be significant independent predictors of achieved height as well as weight, controlling for age. Our results suggest that onset of puberty is substantially delayed among Turkana males, and that bioavailable T is related to growth in stature during adolescence. We suggest that SHBG acts to mediate the effects of energy availability on adolescent growth in this energetically limited population. Our findings may also have implications for understanding adolescent growth among Homo erectus.     

Age-related patterns of urinary gonadotropins (FSH and LH) and E-3-G as measures of reproductive function among Turkana males of northern Kenya

To determine age-related patterns of gonadotropins and their relationship to energetic status in a subsistence population we analyzed urinary FSH, LH, and estrone-3-glucuronide (E-3-G) along with anthropometric measures among Turkana males of northern Kenya. Subjects were 134 nomadic and 109 settled males ages 20 to 80+. FSH, LH and E-3-G were significantly higher among the settled, compared to nomadic, males. LH, but not FSH, showed a significant increase across 10 year age groups among all the men. E-3-G increased across age groups only among the settled males. Controlled for age, FSH was inversely related to measures of fat free and body mass among the settled men. These findings suggest an unusual age profile of gonadotropins and estrogen metabolites that may reflect the impact of fluctuating food availability. More research is needed to address the impact of energetic and social factors on the male reproductive axis among energetically stressed populations.     

Modeling the effects of maternal nutritional status and socioeconomic variables on the anthropometric and psychological indicators of Kenyan infants from age 0-6 months

This paper presents a comprehensive empirical analysis of the factors affecting growth and psychological development of over 100 infants from birth to age 6 months in the Embu region of Kenya. The analysis was divided into four parts. First, infants' birth weight, and length and head circumference as measured few days after birth, were modeled using multiple regression models. Maternal prepregnancy body mass index (BMI), gestation period, and parity were associated with infants' anthropometric measurements (P < 0.05). Second, the scores on seven clusters of the Brazelton Neonatal Behavioral Assessment Scale were explained by health and socioeconomic indicators. While the models had poor predictive power, the scores were comparable to those reported in the literature for Puerto Rican and African American infants. The third part of the analysis modeled infant growth between 1-6 months by analyzing longitudinal data on length, head circumference, and weight. Dynamic models were postulated for the effects of nutritional, socioeconomic, and environmental factors and morbidity on anthropometric variables. The results showed that infants' calcium intakes were positively associated with length (P < 0.05). Maternal BMI and hemoglobin concentration were positively associated with infant weight (P < 0. 05); infant morbidity was negatively associated with weight (P < 0. 05). Lastly, the infants' scores at 6 months on the Bayley Motor Scale and on eight items from the Bayley Infant Behavior Record were explained using anthropometric, socioeconomic, and psychological variables. The infants' arm circumference and intake of protein were significant predictors of scores on the Bayley Motor Scale. In addition, time spent by the mother talking to the infant was positively associated with the scores on the Bayley Infant Behavior Record. The empirical results have implications for identifying vulnerable children in developing countries.     

Differential mortality in Turkana agriculturalists and pastoralists

Nomadic pastoral populations appear to have much lower rates of growth than the otherwise very high growth rates now characteristic of populations in developing nations. Because dramatic declines in infant mortality have been a primary contributor to increased population growth rates in these countries, it has been assumed that nomadic pastoral populations are still characterized by high levels of mortality in the first few years of life. Few studies, however, have been undertaken to estimate demographic parameters for nomadic pastoral populations, and even fewer of a comparative nature have been undertaken to document the impact of subsistence strategy on demographic processes. This study compares indirect childhood mortality estimates for Turkana nomadic pastoralists with childhood mortality in a settled agricultural group within the same population and finds that pastoralists have substantially higher levels of mortality. Based on the childhood mortality estimates, model life tables are selected for pastoral and agricultural groups from which values for mean life expectancy and infant mortality are estimated and compared. Recent improvements in primary health care for the settled agricultural group are ruled out as being an important cause of their lower mortality levels, and some aspects of life-style associated with subsistence strategy are discussed as likely determinants of the mortality differences.     

Cross-sectional growth of young Shipibo Indian children in eastern Peru

This paper reports measurements of weight and recumbent length for a cross-sectional sample of 149 Shipibo infants and children between birth and 35.99 months of age from eight villages in the Peruvian Amazon Basin. The Shipibo are an Amerindian population experiencing a period of local environmental disruption and rapid cultural change. Compared with the National Center for Health Statistics (NCHS) references values, Shipibo children are smaller and shorter than American children. The differences are least at birth. Deficits in linear growth begin between 3 and 6 months of age and continue through 35.99 months of age. Weight-for-length ratios are generally adequate compared to the NCHS values in all age groups. This pattern of growth is similar to that reported for non-Amerindians in many developing countries and is assumed to represent a pattern of growth under mild-to-moderate undernutrition. High infant mortality rates suggest that an interaction of suboptimal nutrition and infectious diseases is contributing to the pattern of growth retardation seen; however, genetic differences cannot yet be discounted.     

Birth weight,length, head circumference and bilirubin level in Indian newborns in the Sioux Lookout Zone,northwestern Ontario.

The norms for birth weight, length, head circumference and bilirubin level for native newborns have not been available. To develop appropriate norms, data were obtained from the charts on all live births in the Sioux Lookout Zone, northwestern Ontario, in 1968-69 and 1974-77. These data were correlated to maternal age and parity as well as sex of the infant. Despite impoverished living conditions, the birth weights of the study population were significantly higher than the Canadian norms; length and head circumference, however, were not significantly different. Over one third of the infants had serum bilirubin levels greater than 12 mg/dL (205 mumol/L). Increased maternal age was associated with increased birth weight and length and a lower bilirubin level.     

Longitudinal growth of head circumference in Punjabi infants in Chandigarh (India)

One hundred and fifty four (86 male and 68 female) Punjabi infants residing in Chandigarh (India) were longitudinally measured for head circumference at monthly age intervals during first year of life. The general pattern of growth of head circumference was characterised by initial sharp rise followed by slow gain during second half of infancy. Beyond birth male infants, possessed higher and statistically significant mean values than their female counterparts. The pattern-wise similarity between growth curves plotted for Punjabi and Western infants, may be attributed to protective effects of breast feeding. Head circumference velocity showed rapid deceleration immediately after birth up to about 4 months, thereafter, it declined slowly. Sex differences in monthly growth rates were found to be statistically significant (p<0.05) at a few of the age intervals during first year of life.     

Growth and development of infant giant pandas (Ailuropoda melanoleuca) at the Wolong Reserve,China

From 1991 to 1993 inclusive, seven infant giant pandas (Ailuropoda melanoleuca) were born at the China Conservation and Research Center for the Giant Panda. Average daily weight gain in the first 6 months for mother-reared infants (n = 5) was 71.3 g/day; for one partially mother-reared and partially hand-reared infant, 41.5 g/day; and for one completely hand-reared infant, 50.3 g/day. There was a significant difference in growth rates across the first 6 months in all methods of rearing. In addition, a comparison of growth rates across the three rearing methods showed significant differences in the first, second, third, fifth, and sixth months. Average daily body length increase for mother-reared infants was 4.1 mm/day; for partially mother-reared/partially hand-reared infants, 4.0 mm/day; and for the completely hand-reared infant, 2.8 mm/day. In mother-reared infants, body length increase during the first month was significantly greater than during the following months, and was slowest during the sixth month. At birth, infants were all pink in color with a light white coat of lanugo. Black pigmentation was first noted at 7–10 days of age, which was also the time that initial hair coat growth was seen. Eyes opened at 35–48 days of age. Ears opened at 31–50 days of age. Deciduous dentition was first seen at 82–121 days of age, while permanent dentition began to erupt at 350 days of age. © 1996 Wiley-Liss, Inc.     

Relationship between parameters of early growth in Israeli infants

A sample of 1931 Israeli infants was measured for body weight (WT), length (HT) and head circumference (HC) for approximately 2 years. The Count model with 3 parameters was chosen as the best fitting and most parsimonious function to approximate growth of all 3 studied traits. In the model parameter a relates to birth indices, b--to velocity of growth, and c--to rapid early childhood growth, or acceleration. Assuming a difference in growth patterns in the periods of different length, the whole sample was divided into 3 groups: 1) infants with last measurement around the age of 12 months; 2) infants with last measurement around the age of 18 months, and 3) infants with last measurement around the age of 24 months. The individuals measured up to 12 months were presented in all three groups. 27 curve fitting parameters, corresponding to 3 different follow-up intervals for WT, HT and HC were computed for each individual. A high correlation was detected between the a parameters regardless of time interval for 3 measured traits. A negative correlation was found between b and c parameters within the same time interval. A consistent positive correlation was indicated between a and b parameters, especially for body length and head circumference. A principal component analysis extracted five independent factors explaining 88.1% of the total variance. Three first factors retained parameters b and c, describing growth rate and pattern of each trait separately, namely, F1 was responsible for head circumference, F2 was a body length factor, F3 was a body weight factor. F4 extracted all birth indices, observed (HC0, HT0 and WT0) and expected (parameters a). The composition of principal factors allowed us to assume that there might be a strong involvement of a pleiotropic genetic source in determination of birth size traits and an independent genetic source controlling the pattern of growth for each trait separately.     

Rate of growth in length of Bangladeshi infants as a function of attained length.

We examine variation in the rate of growth in length of breast-feeding infants from rural Bangladesh. These data were collected between November 1985 and February 1986 from two rural sites. Eighty-eight infants, ranging from birth to 4 months of age at the start of the study and their mothers were measured monthly for 4 months. Length increased linearly with age over this 4-month period (infants' average bias-adjusted R2 = 0.90). The relationship between infant rate of growth in length and attained length was analyzed by two different methods: Oldham's (1962) method of regressing rate of growth on mean length and Blomqvist's (1977) method of regressing rate of growth on estimated initial length. The methods gave similar results. The rate of growth was negatively associated with mean infant length over the 4-month period (p less than 0.001); that is, shorter infants grew at a faster rate than longer infants. For every centimeter shorter the infant was, the rate of growth was 0.1 cm/mo faster on average; the effect was greater among males than among females. The average rate of growth was greater for males than for females and greater in financially solvent households and varied by site. Infant growth rate was slower among older infants than among younger infants, as expected. However, after adjusting for mean infant length, age was no longer significantly associated with infant growth rate, although mean infant length remained highly significant. Forty-one percent of the variation in infant rate of growth in length was explained by mean infant length, sex, sex by length interaction, household financial solvency, and site.     

Individual variation in the growth of captive infant gorillas

Serial anthropometric data were obtained during the first year of life of six nursery-reared infant gorillas in the Columbus (Ohio) Zoo. Two of the infants are likely to be monozygotic twins as determined by DNA analysis. Growth curves were fitted to serial measures of cephalo-thoracic-abdominal length, arm length, leg length, head circumference, upper arm circumference, and weight from each gorilla, to describe individual patterns of variation in skeletal growth and body composition. Growth in skeletal measures tended to be curvilinear to varying degrees over the first year of life. Body composition varied more than skeletal measures throughout the first year as a consequence of individual health status. Individual growth and body composition variations appear to reflect both genetic and environmental influences in this small sample of captive infant gorillas.     

Maternal and fetal nutrition in south India.

The relation between the nutrition of the mother and that of her baby was assessed in a south Indian community where malnutrition is common and women do not smoke. Unselected mothers and their infants of over 37 weeks'' gestation were studied in two groups: those who paid for their care (150) and a poorer group who did not (172). There were significnat differences between the paying and non-paying groups in maternal triceps skinfold thickness, infant weight, and infant length. Overall there was a significant positive correlation between maternal triceps thickness and infant weight, length, and triceps and subscapular skinfold thickness. The correlation with the infant head circumference was less significant. These findings are further evidence that the nutrition of the mother has an important effect on the nutrition of her baby and that malnutrition is an important reason why Indian babies are lighter than European ones.     

Body Proportions of the Infant

Growth is usually evaluated by single measurements which reflect only that direction of growth. At birth the relationship between measurements is often considered as Rohrer's Ponderal Index which describes weight in relation to length but can be misleading especially when considering premature infants. We propose that it is more appropriate to study the relationship of different anthropometric measurements to define normality and thereby create limits from which abnormalities in growth may be diagnosed. Weight, crown heel length, crown rump length and head circumference were measured in 305 healthy infants, at 26–42 gestational weeks to obtain reference values. Subischial leg length was calculated. A multivariate model was made which could be useful to distinguish the form and shape of an infant and to identify abnormalities in growth.     

Relationships between pregnancy spacing,sex of infants,maternal age,and birth order,and neonatal and post‐neonatal mortality in Bangladesh

Abstract

The relationships between length of the interpregnancy interval, outcome of the pregnancy preceding the interval, sex of the infants, pregnancy order, maternal age, and maternal history of previous child deaths and neonatal and postneonatal mortality were explored in a rural Bangladeshi population using a multiple regression analysis. Specific interactions between the interpregnancy interval, outcome of the pregnancy preceding the interval, sex of the infants, and history of previous child deaths were examined. An inverse relationship was observed between postneonatal mortality and the length of the interpregnancy interval when the pregnancy preceding the interval was a surviving infant. No such trend was observed for neonatal mortality. Post‐neonatal mortality rates among children whose mothers had experienced two or more previous child deaths were essentially the same as that for infants whose mothers had experienced 0–1 child deaths when the interpregnancy intervals were more than 24 months. Although female infants have a lower neonatal mortality than male infants, the neonatal mortality rate for female infants conceived less than twelve months following a male infant birth was higher than for a male infant conceived less than twelve months following another male infant birth. Post‐neonatal mortality is consistently higher for female compared to male infants in all interval categories.     

Extreme seasonality of births among nomadic Turkana pastoralists

Births to nomadic Turkana women in northwest Kenya follow one of the most highly seasonal distributions ever reported for a human population, with more than half of all births falling between March and June. Important aspects of the Turkana environment also fluctuate greatly over the course of the year. The rate of conception is apparently highest during the early dry season, when the food supply has been at its best for some time, and when women are attaining their peak nutritional status. The seasonal dynamics of Turkana fertility seem to be driven, ultimately, by fluctuations in rainfall; Fourier analysis indicates that changes in numbers of conceptions follow changes in rainfall with a lag of 3.6 months. The specific biological and behavioral changes in the human population through which the environmental changes may affect fertility are considered.     

A biocultural investigation of the weanling's dilemma in Kathmandu, Nepal: do universal recommendations for weaning practices make sense?

The primary objective of this report is to use data from a study of infant growth and weaning practices in Kathmandu, Nepal, to investigate universal recommendations about exclusive breast-feeding up to 6 months postpartum. A secondary objective is to demonstrate the complexity of the biocultural nature of infant feeding practices. A sample of 283 children under 5 years of age and their 228 mothers living in a peri-urban district of Kathmandu participated in this study. The children's height/length and weight were measured three times over 9 months. At each session, a demographic, child health and infant feeding survey was administered; between sessions, in-depth interviews were conducted with mothers regarding infant feeding practices. While a few of the infants under 2 months were receiving non-breast milk foods, at 3 months of age half of the sample had been introduced to non-breast milk foods and by 7 months all infants were eating non-breast milk foods. A comparison of growth indices and velocities between exclusively and partially breast-fed infants from birth to 7 months of age shows no evidence for a difference in nutritional status between the two groups. Although there are cultural rules about breast-feeding that vary by ethnic group, all mothers followed a feeding method that depended on their assessment of whether the child was getting enough breast milk. The conclusion is that exclusive breast-feeding up to 6 months may not be appropriate for all infants. In this sample, breast-feeding duration is not shortened by the early introduction of non-breast milk foods, as the median age of breast-feeding cessation is 36 months. One of the main reasons for severance was the onset of another pregnancy. Investigation of infant feeding practices must be contextualized in the local ecology of the population. While cultural beliefs about breast-feeding are relevant, mothers' individual assessments of their children's nutritional needs and demographic events in parents' lives must also be considered.