Why Are Poorer Girls Twice As Likely to Start Their Period By 11?
Girls who come from poorer families are two-and-a-half times more likely to start their period by the age of 11, than children from wealthier backgrounds.
That's according to new research from the ESRC International Centre for Lifecourse Studies in Society and Health, which shows that affluence is the largest indicator of early puberty.
‘Early puberty in 11-year-old girls: Millennium Cohort Study findings’ is the first study to look over time at whether, and how, a girl’s social and economic circumstances and her ethnicity might be linked to the early onset of puberty.
The report, completed at UCL (University College London), examined information from 5,839 girls who have participated in the Millennium Cohort Study which has been tracking the lives of 19,000 UK children born in 2000-01.
While the average age for UK girls to start their menstrual cycle is 12.9 (12 years, and nearly 11 months), the study found that:
- On average, girls who were heavier at age seven and suffered stress in early childhood were more likely to have begun menstruating by age 11
- Those who had started their periods early also tended to have mothers with higher stress levels, were from single-parent families, and tended to have had some social and emotional difficulties themselves
- Indian, Bangladeshi and black African girls were most likely to have started their period at age 11, with Indian girls three-and-a-half-times more likely than their white counterparts to have done so.
Early puberty is linked to numerous health outcomes including increased risk of poor mental health (in adolescence and throughout life), cardiovascular disease and some cancers.
To identify markers for earlier menstruation, Professor Yvonne Kelly and the team of academics at UCL looked at a number of factors including income, weight, ethnicity, stress and parental situation.
“After we took account of factors including their weight and early life stress, girls from the poorest and second poorest groups were still one and a half times more likely to have started their periods early. And as far as ethnicity was concerned, income, excess body weight and stress accounted for part or all of the differences in most cases,” explained Professor Kelly.
“The findings can perhaps be explained, as we know that girls from less wealthy backgrounds are more likely to have a higher BMI (body mass index), and their mothers are more likely to experience psychological distress – all of which appear to be an indicator of beginning menstruation earlier in life.”
The study, which has been published in Archives of Disease in Childhood, showed that one in 10 girls are starting their period by age 11 years of age.