Author Author Author

PH251 Date

Is Father Absence Early in Life Associated with

Age at Menarche?

Overview

IntroductionMethodsResultsDiscussion

Research Question

Is father absence at age 5 associated with age at menarche in the California Child Health and Development Studies (CHDS) Cohort?

Background

Public Health Implications of Earlier Menarche: Breast cancer, obesity, type II

diabetes Conduct & behavioral disorders Substance Abuse Depression & Eating Disorders Teen Pregnancy

Background

Average age about 12 1/2 But wide variation Variation depends on:

Race/ethnicityMaternal Age at MenarcheBMIFamily Environment Early in Life

Father AbsenceSibling Composition

Father Absence Theories

Psychosocial Acceleration Theory

Chemosignal (Phermone) Theories

Paternal Investment TheoryEnergetics TheoriesLife History Theory

Hypotheses

Girls with father absence at age 5 will have earlier age at menarche.

Father absent girls with more siblings will have a later age at menarche than father absent girls with less siblings.

Review of the Literature

Several studies found association

Campbell & Udry (1995) did NOT find this effect at age 5 in CHDS cohort…WHY NOT? Strange covariates in model? Statistical models used? Effect modification?

Overview

IntroductionMethodsResultsDiscussion

Study Participants

20,754 pregnancies in the CHDS

3,587 live, female births with no congenital anomalies born between June 1960 and January

1963

850 participated in five year 1, nine to eleven, and adolescent

examinations

748 provided information on father absence at age 5, age at menarche, and sibling composition

at age 5

Exposure

Father absence at age 5: Five Year 1 Examination Based on maternal report “Mother only” or “Mother +

Stepfather”

Outcome

Age at menarche Adolescent Examination Self-reported Years, not months

Covariates

Chosen a priori from the literature: Race Maternal age at menarche Social class BMI – mediator Siblings (total #, older male, older female)

Confounders included in statistical model if their removal changed the coefficient on father absence by ≥ 10%

Statistical Analysis

Statistical Models Linear regression Logistic regression Polytomous logistic regression Cox proportional hazards regression

Effect Modification Sibling composition Race

Sensitivity Analysis

Overview

IntroductionMethodsResultsDiscussion

Descriptive Statistics

93%

7%

Number & Percent of Girls with Father Absent

& Present at Age 5

Father Present(n=695)

Father Absent(n=53)

60%

15.8%

24.2%

Percent of Girls with Early, Normal & Late

Menarche Normal Menarche(12-13)Early Menarche(< 12)Late Menarche(> 13)

Covariates Associated with Father Absence

Race Maternal age at menarche Social class BMI Total # of Siblings Total # Older Brothers Total # Older Sisters

Covariates Associated with Age at Menarche

Race Maternal age at menarche Social class BMI Total # of Siblings Total # Older Brothers Total # Older Sisters

Crude Association

No difference in mean age at menarche by exposure (P = 0.5) Father absent girls: 12.6 Father present girls: 12.7

Multivariate Model Results

Dichotomous Logistic Regression: OR=1.4 (0.6, 2.9)

Polychotomous Logistic Regression: OR=1.3 (0.6, 2.8) (Early vs. Normal) OR=0.9 (0.4, 1.9) (Late vs. Normal)

Multivariate Linear Regression: β=-0.2 (-0.5, 0.2)

Cox Proportional Hazard Regression: HR=1.0 (0.4,1.8)

Interaction

Interaction terms tested using all our modeling approaches. Father absence x number of siblings Father absence x number of older sisters Father absence x number of older brothers Father absence x race

No evidence of interaction. All p-values > 0.5

Sensitivity Analysis

Recoded individuals living with “grandparents” and “other” as father absent.

Included individuals missing sibling information at age 5 and age 9-11.

Used maternal age at menarche data from just the BASIC dataset and just the PNWORK dataset.

Overview

IntroductionMethodsResultsDiscussion

Findings

Findings do not support father absence/sibling theories

Findings do not support most other literature

Findings DO support Campbell & Undry’s findings from 1995

Strengths

Sample size Study Design Statistical Methods

Multiple Multivariate Regression Models

Covariates Considered Interactions Considered Sensitivity Analyses

Limitations

Recall Bias Father Absence Variable

Small n Time of father absence unknown Stepfather presence not considered

Pubertal Timing Indicator SES Variable Quality of Family Relationships

Future Research

MEASURE STRESSMEASURE

PUBERTAL ONSET