Early Puberty Sets Girls Up for Future Mental Health Issues
Girls who enter puberty early may have a higher risk for mental health problems in adulthood than their later-developing peers, new research suggests.
In a study of more than 7800 women in their 20s and 30s, depression and antisocial behaviors were more common among those reporting menarche at 7 to 10 years of age compared with women who began menstruating at around 12 years of age, lead author Jane Mendle, PhD, from the Department of Human Development, Cornell University, Ithaca, New York, and colleagues write. They report their findings in an article published online December 26 and in the January 2018 issue of Pediatrics.
These findings suggest that the challenges associated with early development "are not transient growing pains," but "may place girls on a life path from which it may be difficult to deviate," they add. Given that the age of puberty has declined during the past 50 years, the paucity of studies on this subject represents "not merely a gap in the research literature but a public health issue."
In fact, younger age at menarche may be an indication to begin depression screening before 12 years of age, which is the current recommendation of the US Preventive Services Task Force, Ellen Selkie, MD, MPH, from the Division of Adolescent Medicine, Department of Pediatrics, University of Michigan School of Medicine, Ann Arbor, writes in an accompanying commentary.
An Unanswered Question
Despite a well-documented association between early puberty in girls and a higher risk for several mental health issues during adolescence, such as depression, anxiety, eating disorders, and substance abuse, the implications for mental health later in life have not been extensively studied, the authors explain.
To explore this issue, the researchers used data from the National Longitudinal Study of Adolescent Health, a nationally representative study of health and risk behavior among adolescents. The data were collected in four "waves" between 1994 and 2008 and represent "a high degree of racial, ethnic, and socioeconomic diversity," the authors explain.
This analysis consists of data on 7802 women who underwent an initial in-home interview (wave I) in 1994, at a mean age of 15.8 years (range, 11 - 21 years). In wave II, follow-up interviews were conducted during 1995 to 1996, when the participants were a mean age of 16.1 years (range, 12 - 23 years). Wave III interviews took place during 2001 to 2002 (mean age of participants, 21.7 years; range, 18 - 27 years), and wave IV took place during 2007 to 2009 (mean age of participants, 28.7 years; range, 24 - 34 years).
Most of the women said they began menstruating at age 12 or 13 years (reported by 31.59% and 24.40%, respectively). However, 10.34% achieved menarche at 7 to 10 years of age, with another 19.17% starting menses at 11 years of age. The frequency of menarche dropped off sharply after age 13 years, although at least one person reported it as late as 24 years of age.
Earlier Menses, More Depression
As in earlier studies, a relationship between younger age at menarche and depressive symptoms during adolescence emerged, the authors write. However, this relationship was still apparent in wave IV, when the participants were nearly 30 years of age. In a statistical model analyzing depressive symptoms at wave IV with age at menarche and demographic and familial covariates such as race and socioeconomic status, "menarche was both linearly (b = −0.84; P <.05) and quadratically (b = 0.03; P < .05) associated with symptoms."
This finding translates into "an effect of 6% of 1 [standard deviation] for a girl who reached menarche at age 10 years and 20% of 1 SD for those who reached menarche at age 8 years relative to those who reached menarche at 12 years," and suggests that "effects are more pronounced and menarche is more steeply related to depressive symptoms when it occurs at a younger age."
The findings also suggest that girls who reach puberty early are more vulnerable to depression in adulthood than their peers who mature later "primarily because they become depressed as adolescents, and this vulnerability persists over the next decade and one-half."
Similarly, antisocial behavior during adolescence was significantly and linearly related to age at menarche, an effect that persisted into adulthood, although the significance in adulthood was marginal (P = .08). However, "it may also be possible that antisocial behaviors slightly worsen in adulthood for early-maturing girls relative to later-maturing girls," the authors warn.
Dr Selkie lists several mechanisms that might account for this effect of early puberty on mental health. Biologically, early production of estradiol may affect the production of serotonin receptors, or chronic stress may "accelerate the activation of the hypothalamic-pituitary-gonadal axis and contribute to early puberty."
Socially, children who appear older than they are may be treated as such by peers and adults, which may also contribute to stress and depressive symptoms, Dr Selkie writes. There is also a relationship between overweight or obesity and early puberty, so the stigma of being heavy may exacerbate the stress that early puberty brings.
And when it comes to antisocial behavior, girls who enter puberty earlier "may seek out friends who are older than them to fit in with peers who look like them, but they may feel pressured to then engage in risky behaviors," she adds.
These findings suggest that "the emotional sequelae of puberty may endure well past the proximal period of adolescence," Dr Mendle and colleagues conclude. "Pediatricians should be attuned to the mental health risks associated with earlier puberty and be sensitive to the duration of its effects."
Pediatrics. 2018;141(1):e20171703, e20173460. Article abstract, Commentary extract