Menarcheal age in two generations of South African Indians.

Intergenerational and socioeconomic effects on menarcheal age were investigated in a sample of 146 mother-daughter pairs of South African Indians living in the urban area of Lenasia, Gauteng Province. Information on menarcheal age, socioeconomic status, and educational attainment of both parents was obtained by questionnaire. Data on menarcheal age of daughters were analysed by probit analysis and descriptive statistics. Mean maternal menarcheal age was 13.20 years (SD = 1.57) and was significantly greater than the menarcheal age of the postmenarcheal daughters at 12.52 years (SD = 1.25) and of mean menarcheal age analysed by probits of 12.40 years (SD = 1.18). Mother-daughter menarcheal ages were significantly correlated (r = 0.23; p < 0.035). This association was confounded by the significant association of maternal menarcheal age to the age at which mothers recalled that event (r = 0.32; p < 0.003). Partial correlations demonstrated that the mother-daughter correlation reduced to a non-significant 0.16 (p < 0.14) after maternal age at recall had been controlled. No significant associations were found between socioeconomic variables and menarcheal age except for family size, in which girls with more than three siblings had significantly later menarcheal ages than girls with three siblings. Secular trends for reduced menarcheal ages were evident in both the intergenerational data (0.24 years/decade) and in comparison to the data of Kark (1953) from four decades ago (0.27 years/decade).