Parental age at childbirth and age of menarche in the offspring

The influence of parental age on timing of puberty: A study in the Danish National Birth Cohort

Aims: Concerns have been raised about the potential negative biological effect of postponed parenthood upon the health of subsequent generations, including reproductive health. This study aimed to estimate if high parental age at birth was associated with accelerated pubertal timing in offspring. Methods: In this large-scale cohort study, 15,819 children born by mothers in the Danish National Birth Cohort from 2000 to 2003 participated in a nationwide puberty cohort (participation rate 71%). Between 2012 and 2018, the children reported half-yearly information on pubertal status using web-based questionnaires from 11 years throughout puberty or 18 years of age. Information on parental age was drawn from nationwide registers. We estimated adjusted mean differences in months for age at attaining the pubertal milestones and pubertal timing overall between the pre-specified parental age groups: 20-29 (reference), 30-34 and advanced parental age groups (35-44 years for mothers and >35 years for fathers). Results: Overall, parental age at birth of the child was not associated with pubertal timing in daughters or sons. For sons of older fathers (>35 years), we observed indications towards slightly earlier pubertal timing in the range of 0.3-2.4 months for nearly all pubertal milestones, but all confidence intervals were wide, and many included the null. Conclusions: We found no strong association between parental age and timing of puberty, and we find it unlikely that the decreasing age in pubertal timing is a result of parental decision to delay childbearing.

Factors associated with early age at menarche among Thai adolescents in Bangkok: A cross-sectional study

Background

The age at menarche in the Thai population has not been determined since 1997. This study recruited adolescents in Bangkok Metropolis to determine the age at menarche and its associations with health and socioeconomic status.

Methods

This cross-sectional study used a two-step stratified sampling strategy to recruit 1,020 female students, aged 10–16 years, from schools in Dusit district, Bangkok, Thailand. Self-reported data on age at menarche and social determinants of health were collected from participants and their parents. A trained research nurse collected anthropometric data.

Results

Mean age at menarche was 11.8 ± 1.0 years, and age at menarche was significantly correlated with year of birth (r = −0.4, p < 0.001). Students from schools that are part of Bangkok Metropolis had the lowest mean age at menarche. Participants born in 2000–2003 having their first period at < 11.8 years numbered 5.5 times (95% CI: 3.80–8.18) and 5.0 times (95% CI: 3.6–8.0) greater than those born in 1997–1999 by univariate and multivariate analysis, respectively. Year of birth significantly associated with age at menarche in univariate and multivariate analysis (p = 0.001).

Conclusion

The mean age at menarche among female adolescents in Bangkok Metropolis was occurring earlier and was inversely associated with year of birth in this cohort. Only year of birth were associated with age at menarche in the multivariate regression models to adjust for potential confounders.

Prenatal and infant exposures and age at menarche

BACKGROUND

Early menarche is related to increased risk of breast cancer. The number of established factors that contribute to early menarche is limited. We studied prenatal and infant exposures in relation to age at menarche in a nationwide cohort of women who have a family history of breast cancer.

METHODS

The study comprised 33,501 women in the Sister Study who were 35-59 years of age at baseline (2003-2009). We used polytomous logistic regression to estimate separate relative risk ratios (rRRs) and 95% confidence intervals (CIs) for associations of self-reported exposures with menarche at ≤10, 11, 14, and ≥15 years relative to menarche at 12-13 years.

RESULTS

Early menarche (≤10 or 11 years) was associated with having low birth weight, having had a teenage mother, being firstborn, and specific prenatal exposures: mother's smoking, diethylstilbestrol (DES), prepregnancy diabetes, and pregnancy-related hypertensive disorder. Prenatal exposures most strongly associated with very early menarche (≤10 years) were DES (rRR = 1.56 [95% CI = 1.24-1.96]), maternal prepregnancy diabetes (2.24 [1.37-3.68]), and pregnancy-related hypertensive disorder (1.45 [1.18-1.79]). Soy formula was associated with both very early menarche (1.21 [0.94-1.54]) and late menarche (14 years: 1.17 [0.98-1.40] or ≥15 years: 1.28 [1.06-1.56]).

CONCLUSIONS

Although menarche is only one marker of pubertal development, it is a commonly used surrogate. The observed associations of prenatal DES and soy formula exposure with age at menarche are consistent with animal data on exogenous estrogens and pubertal timing. Early-life exposures may confound associations between age at menarche and hormonally dependent outcomes in adults.

Using web-based and paper-based questionnaires for collecting data on fertility issues among female childhood cancer survivors: differences in response characteristics

BACKGROUND

Web-based questionnaires have become increasingly popular in health research. However, reported response rates vary and response bias may be introduced.

OBJECTIVE

The aim of this study was to evaluate whether sending a mixed invitation (paper-based together with Web-based questionnaire) rather than a Web-only invitation (Web-based questionnaire only) results in higher response and participation rates for female childhood cancer survivors filling out a questionnaire on fertility issues. In addition, differences in type of response and characteristics of the responders and nonresponders were investigated. Moreover, factors influencing preferences for either the Web- or paper-based version of the questionnaire were examined.

METHODS

This study is part of a nationwide study on reproductive function, ovarian reserve, and risk of premature menopause in female childhood cancer survivors. The Web-based version of the questionnaire was available for participants through the Internet by means of a personalized user name and password. Participants were randomly selected to receive either a mixed invitation (paper-based questionnaire together with log-in details for Web-based questionnaire, n = 137) or a Web-only invitation (log-in details only, n = 140). Furthermore, the latter group could request a paper-based version of the questionnaire by filling out a form.

RESULTS

Overall response rates were comparable in both randomization groups (83% mixed invitation group vs 89% in Web-only invitation group, P = .20). In addition, participation rates appeared not to differ (66% or 90/137, mixed invitation group vs 59% or 83/140, Web-only invitation group, P =.27). However, in the mixed invitation group, significantly more respondents filled out the paper-based questionnaire compared with the Web-only invitation group (83% or 75/90 and 65% or 54/83, respectively, P = .01). The 44 women who filled out the Web-based version of the questionnaire had a higher educational level than the 129 women who filled out the paper-based version (P = .01). Furthermore, the probability of filling out the Web-based questionnaire appeared to be greater for women who were allocated to the Web-only invitation group (OR = 2.85, 95% CI 1.31-6.21), were older (OR = 1.08, 95% CI 1.02-1.15), had a higher educational level (OR high vs low = 0.06, 95% CI 0.01-0.52), or were students (OR employed vs student = 3.25, 95% CI 1.00-10.56).

CONCLUSIONS

Although overall response as well as participation rates to both types of invitations were similar, adding a paper version of a questionnaire to a Web-only invitation resulted in more respondents filling out the paper-based version. In addition, women who were older, had a higher level of education, or were students, were more likely to have filled out the Web-based version of the questionnaire. Given the many advantages of Web-based over paper-based questionnaires, researchers should strongly consider using Web-based questionnaires, although possible response bias when using these types of questionnaires should be taken into account.

TRIAL REGISTRATION

Nederlands Trial Register NTR2922; http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=2922 (Archived by WebCite at http://www.webcitation.org/5zRRdMrDv).