A survey of the nutritional status of schoolchildren. Relation between nutrient intake and socio-economic factors

Is the number of siblings associated with dietary patterns in adolescents? The 1993 birth cohort of Pelotas (Brazil)

Our study aimed to estimate the association between number of siblings and dietary patterns in adolescents. Prospective longitudinal study was developed using data from the birth cohort of the city of Pelotas, Brazil, which included 5249 participants. At the 18-year-old follow-up, from 4563 individuals located, 4106 were interviewed (follow-up rate 81.3%). Of these, 3751 were included in our principal component analysis of dietary patterns. Regular dietary intake of 45 food groups over the previous year was measured with a food frequency questionnaire. We identified four patterns, which accounted for 40% of the total variance in food group consumption. These were labeled "Protein and fast food", "Fruit and vegetables", "Common Brazilian", and "Sweets, soft drinks, and dairy products". Crude and adjusted analyses of the association between number of siblings and dietary patterns were performed using linear regression. The number of siblings was positively associated with a higher adherence to each dietary pattern, with the exception of the "Common Brazilian" patterns, for which there was no apparent relationship with number of siblings. The findings showed that a greater number of siblings is related to a more diverse diet in the later adolescence, which may predict better nutrient adequacy and health outcomes.

Environmental factors influencing growth and pubertal development

Postnatal growth is based on hereditary signals and environmental factors in a complex regulatory network. Each factor must be in an optimal state for normal growth of the child. Fetal conditions may also have consequences on postnatal height. Intrauterine growth retardation can be recovered postnatally, although postnatal growth remains depressed in about one-third of cases. After birth, the environment may exert either a positive or negative effect on growth. In underdeveloped countries, malnutrition plays a major role in inhibiting the growth process. Children from families of higher socioeconomic classes are taller than their coevals in the lower socioeconomic groups. Urbanization also has a positive effect on growth. Better child care is supported by sufficient food supply, appropriate health and sanitation services, and a higher level of education. Over the last century, these factors have induced a taller stature and a more rapid maturity in Europe, North America, and Australia; a phenomenon which has been referred to as "the secular trend" in growth. Recently, a secular trend has also been reported in some developing countries. Although urbanization in general appears to be associated with better conditions of living, this is not the case in the slums of South America or in Africa where rural children are better off than children living in the poor cities. This paper describes in more detail the different hereditary and environmental factors that act during the fetal period and postnatally, and which play a role in human growth and pubertal development.

Prevalence of obesity in British children born in 1946 and 1958

The prevalence of overweight at ages 7 and 11 years and in late adolescence was compared in two nationally representative cohorts of British children born in 1946 and 1958. Overweight was defined as weight that exceeded the standard weight for height, age, and sex by more than 20% (relative weight greater than 120%). The prevalence of overweight among 7 year olds born in 1958 was nearly twice that among those born in 1946. Changes in infant feeding practices, food supply, and level of physical activity might be responsible for this difference. By adolescence the prevalence of obesity in both cohorts had increased but the difference between cohorts had almost disappeared. Around 9% of adolescent girls and 7% of adolescent boys were overweight. If infant feeding practices have an influence on prevalence of overweight at 7 years the data from the two cohorts suggest that such an effect does not persist. In neither cohort was there a significant relation between the prevalence of obesity and social class in boys, but in girls the prevalence was higher among those from the lower socioeconomic groups. Correlation coefficients showing the strength of the relation between relative weights at different ages were remarkably similar for both cohorts. The risk of being obese later in childhood for those who had not been obese at the age of 7 was less than one in 10, whereas for those with a relative weight greater than 130% the risk exceeded six in 10.

Comparative growth of primary schoolchildren from one and two parent families

Data drawn from the National Study of Health and Growth enabled an examination to be made of the attained height, weight for height, and triceps skinfold of children from one and two parent families. Children from one parent families were shorter than children from two parent families; however, once heights had been adjusted for birthweight, number of siblings, mother's height, father's height, and mother's education this was no longer the case. An examination of the adjusting factors showed that low birthweights and shorter parents accounted for the shorter stature of the one parent family children. An examination of weight for height and triceps skinfold measurements indicated an increased tendency towards obesity in the one parent family children, although this difference was not statistically significant. The higher prevalence of low birthweights and shorter parents that account for the shorter stature of one parent children are factors that cannot be ignored in a consideration of the health and growth of this group of children and obesity may be a potential health problem among the one parent family children.