Physique and family environment in girls attending a Welsh college.

Abstract

It is a curious fact of the biology of the modem population of Britain that, whereas there is little association between menarcheal age and social class (Douglas, 1964;Nisbet and Illesley, 1963), there remain by contrast clear differences in height and weight between children of different socioeconomic groups. These physique differences persist into adulthood (Clements and Pickett, 1957;Thomson, 1959). This contrast between menarcheal age and body size is the more surprising since both share in the well-established secular trend towards earlier attainment of the former and increase of the latter (Tanner, 1962(Tanner, , 1965.A recent and continuing study of girls in a Welsh college (Roberts and Dann, 1967), the object of which was to assess the relative contributions of particular factors of the environment to variation in menarcheal age, showed, as in other recent studies in Britain, no detectable effect of socio-economic status on menarcheal age. Possible explanations proposed were that the Registrar General's socioeconomic categories are no longer meaningful in terms of expenditure on food, standards of housing, etc., factors which influence biological development; or that socio-economic differences have been eliminated as effective influences of biological development during the growth of the subjects. In the latter respect the sample was unusually uniform; the years of birth (1939)(1940)(1941)(1942)(1943)(1944)(1945)(1946) and early life of the subjects covered a period of economic stringency and nutritional uniformity, and indeed it was this relative homogeneity that prompted the initial analysis. In

A 12-year study of menarcheal age.

“…With this speculation, amenable to investi-*> I I; Xgation by body composition studies of families, the J t . It I I physique results in the earlier part of this studŷ .1 r t (Dann and Roberts, 1969) do not conflict, for the t regression coefficients of weight and height on family size are negative, whereas those on position in family are positive. 193b.…”

“…Collection of data finally ceased after the 1970 intake, by which time details were available for 2,457 girls. A preliminary note on the study appeared (Dann and Roberts, 1973), and the full analysis of the total is now reported.…”

Secular trends in growth and maturation in British girls

“…In contrast to the variations from analysis to analysis that occurred in menarcheal age, the successive analyses of stature were more consistent. The first analysis of stature after the first 7 years of the Swansea data (Dann and Roberts, 1969) showed a rapid increase in mean stature both overall and within social classes, a t a rate, respectively, of +0.30 and +0.34 cm per year. Stature, but not weight or the ponderal index, was significantly associated with year of birth and social class, but not with family size or birth order.…”

Body structure and maturation – the association with environmental factors

“…Earlier studies on girls studying in the Welsh Collage have revealed that family size tends to diminish height whereas position in family increases height (Dann and Roberts 1969). A multidisciplinary explanation for the findings on family size suggests that family resources become "diluted" as family size increases and the result is the various developmental deficits reported by researchers.…”