| Abstract: | 1866 girls aged 11-15 1/2 years in Northwest Slovakia were interviewed at their schools concerning the age at menarche, number of siblings, and altitude of their residence. 518 of the girls had undergone menarche. An angular transformation of the data was carried out, and an analysis of the variance of percentages of young girls who had attained puberty was performed. An increase in the number of girls attaining puberty with age was observed as expected, but decreases in the proportion attaining puberty at a given age corresponding with an increase in the number of siblings or of altitude were also observed. The age f pubety for those with 0-1 siblings was 14.32 years; for each additional 2 siblings, it increased by about .105 years, or about 5 weeks. The average age of puberty for girls whose homes were located at 450 m above sea level or less was 14.19 years, with each additional 100 meters of altitude adding about .253 years, or 3 months, to the age at menarche. The effects of both altitude and number of siblings were statistically significant. |
