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Author Author Author UC BERKELEY SCHOOL OF PUBLIC HEALTH ▪ Date. Weight status at age 5 and Timing of menarcheal onset. AGE AT MENARCHE.
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Author AuthorAuthor UC BERKELEY SCHOOL OF PUBLIC HEALTH ▪ Date Weight status at age 5 and Timing of menarcheal onset
AGE AT MENARCHE Adapted from maturitychart.org; according to Parent AS et al. The timing of normal puberty and age limits of sexual precocity: variations around the world, secular trends, and changes after migration. Endocrine Reviews; 2003.
AGE AT MENARCHE Anderson et al. (2003). Relative weight and race influence average age at menarche: results from two nationally representative surveys of US girls studied 25 years apart
PUBLIC HEALTH SIGNIFICANCE • Risks associated with early pubertal maturation include: • increased adolescent risk-taking behavior • increased psychosocial problems • adolescent pregnancy • premenopausal breast cancer
BACKGROUND • Evidence suggests a close association between early sexual maturation and obesity in females. • Early-maturing girls are more likely to be heavier (both prospectively and retrospectively) than non-early maturers
Race/ethnicity Maternal age at Menarche Maternal BMI BMI at age 5 Pubertal timing Age at Menarche Smoking during pregnancy Parity Sociodemographic characteristics (income, education, marital status) PLAUSIBLE PATHWAYS
SUMMARY OF LITERATURE • Pubertal girls have higher age- and gender-adjusted BMIs than same-age prepubertal counterparts • Most longitudinal studies have not examined weight status early enough to separate the directionality of weight status and pubertal onset
OBJECTIVE • Assess the association between weight status at age 5 and early menarche
STUDY POPULATION • N=896 • Live, female, singleton births without severe anomalies • Child exclusions: • Born before 1960 or after 1963 • No height or weight at age 5 • Did not attend adolescent exam (did not answer menarche items)
ANALYSIS SAMPLE -2,380 fetal loss / multiple births -9,367 males -295 with birth defects
ANALYSIS SAMPLE -4177 born before 1960 or after 1963 -1135 no ht / wt recorded -2498 did not attend adol exam -6 no ans on menarche items
INDEPENDENT VARIABLE: WEIGHT STATUS • Child height & weight from 5 year exam or from routine visit during 5th year • Body Mass Index (BMI) -for-age percentile • 2000 CDC growth charts • Weight status • Overweight/obese (≥ 85th percentile) • Normal (< 85th percentile)
DEPENDENT VARIABLE: EARLY MENARCHE • Two questions administered at Adolescent Exam • “Have you started your period yet?” • “How old were you when you started your period?” • n=11 responded “no” to question 1 • Age at menarche • Early (< 12 yr) • Non-early (≥ 12 yr)
COVARIATES • Maternal: • Age • Parity • Education • SES (Hollingshead) • Age at menarche • Gestational weight gain • Pre-pregnancy BMI • Smoking status • Child: • Race • Birth weight • Gestational age • Paternal: • BMI
ANALYSIS & MODEL SELECTION • Multivariate logistic regression: • logit(earlyi) = ln(odds of earlyi) = α + β ovobi+ δ Xi • Covariate selection based on bivariate associations and the literature: • Employed backwards elimination and change-in-estimate procedures, removing if ΔOR < 10% • Final model included: race, parity, education, SES, maternal age at menarche, gestational weight gain • Assessed interaction by: • Race
SUMMARY STATISTICS • Overweight/obese weight status: 23.4% • Early menarche: 15.1%
Crude association of weight status & early menarche χ2=9.2 p=0.003
Crude associations of covariates & weight status • Maternal: • Age • Parity • Education • SES (Hollingshead) • Age at menarche • Gestational weight gain • Pre-pregnancy BMI • Smoking status • Child: • Race • Birth weight • Gestational age • Paternal: • BMI
Crude associations of covariates & early menarche • Maternal: • Age • Parity • Education • SES (Hollingshead) • Age at menarche • Gestational weight gain • Pre-pregnancy BMI • Smoking status • Child: • Race • Birth weight • Gestational age • Paternal: • BMI
SUMMARY OF FINDINGS • Significant association between high childhood BMI (overweight/obese at age 5) and early menarche. • Association remains significant after adjusting for race, parity, maternal education, SES, maternal age at menarche, GWG.
POSSIBLE MECHANISMS • Shared environmental factors between mother and child • Endocrine disruptors retained in adipose tissue • Changes in adipocyte cell size and number, proportions of fat and lean body mass influence onset
LIMITATIONS • Model limitations • BMI is a limited measure of adiposity • Menarche is a late marker of puberty • Low R2 for final model • Generalizability • Unmeasured confounders
STRENGTHS • Establishes temporality (prepubertal adiposity) • Cohort was born before current obesity epidemic
IMPLICATIONS • Clinical relevance • Future directions: • Continuous BMI and menarcheal age • Examine parity and sibling mix • Future research: • Other measures of adiposity • Adiposity throughout life course • More evidence from current obesity epidemic and early menarche trends
ACKNOWLEDGEMENTS Special thanks to: Brenda Eskenazi, PhD David Lein, MS Jonathan Chevrier, PhD Maureen Lahiff, PhD MCH and 251A classmates
REFERENCES • Adair LS. Size at birth predicts age at menarche. Pediatrics. 2001;107(4):E59. • Ahmed ML, Ong KK, Dunger DB. Childhood obesity and the timing of puberty. Trends EndocrinolMetab. 2009;20(5):237-42. (doi: 10.1016/j.tem.2009.02.004). • Anderson SE, Dallal GE, Must A. Relative weight and race influence average age at menarche: results from two nationally representative surveys of US girls studied 25 years apart. Pediatrics. 2003;111(4 Pt 1):844-50. • Anderson SE, Must A. Interpreting the continued decline in the average age at menarche: results from two nationally representative surveys of U.S. girls studied 10 years apart. J Pediatr. 2005;147(6):753-60. (doi: 10.1016/j.jpeds.2005.07.016). • Buyken AE, Karaolis-Danckert N, Remer T. Association of prepubertal body composition in healthy girls and boys with the timing of early and late pubertal markers. Am J ClinNutr. 2009;89(1):221-30. (doi: 10.3945/ajcn.2008.26733). • Cooper C, Kuh D, Egger P, et al. Childhood growth and age at menarche. Br J ObstetGynaecol. 1996;103(8):814-7. • Davison KK, Susman EJ, Birch LL. Percent body fat at age 5 predicts earlier pubertal development among girls at age 9. Pediatrics. 2003;111(4 Pt 1):815-21. • Freedman DS, Khan LK, Serdula MK, et al. Relation of age at menarche to race, time period, and anthropometric dimensions: the Bogalusa Heart Study. Pediatrics. 2002;110(4):e43. • Frisch RE, Revelle R. Height and weight at menarche and a hypothesis of critical body weights and adolescent events. Science. 1970;169(943):397-9. • He Q, Karlberg J. Bmi in childhood and its association with height gain, timing of puberty, and final height. Pediatr Res. 2001;49(2):244-51. • Kaplowitz PB. Link between body fat and the timing of puberty. Pediatrics. 2008;121 Suppl 3:S208-17. (doi: 10.1542/peds.2007-1813F). • Kaplowitz PB, Slora EJ, Wasserman RC, et al. Earlier onset of puberty in girls: relation to increased body mass index and race. Pediatrics. 2001;108(2):347-53. • Lee JM, Appugliese D, Kaciroti N, et al. Weight status in young girls and the onset of puberty. Pediatrics. 2007;119(3):e624-30. (doi: 10.1542/peds.2006-2188). • Ruder EH, Hartman TJ, Rovine MJ, et al. Birth characteristics and age at menarche: results from the dietary intervention study in children (DISC). Cancer Causes Control. 2010;21(9):1379-86. (doi: 10.1007/s10552-010-9565-y). • Sloboda DM, Hart R, Doherty DA, et al. Age at menarche: Influences of prenatal and postnatal growth. J ClinEndocrinolMetab. 2007;92(1):46-50. (doi: 10.1210/jc.2006-1378).