Longitudinal association of prepubertal urinary phthalate metabolite concentrations with pubertal progression among a cohort of boys

BACKGROUND

Epidemiological studies have reported associations of anti-androgenic phthalate metabolite concentrations with later onset of male puberty, but few have assessed associations with progression.

OBJECTIVES

We examined the association of prepubertal urinary phthalate metabolite concentrations with trajectories of pubertal progression among Russian boys.

METHODS

At enrollment (ages 8-9 years), medical history, dietary, and demographic information were collected. At entry and annually to age 19 years, physical examinations including testicular volume (TV) were performed and spot urines collected. Each boy's prepubertal urine samples were pooled, and 15 phthalate metabolites were quantified by isotope dilution LC-MS/MS at Moscow State University. Metabolites of anti-androgenic parent phthalates were included: butylbenzyl (BBzP), di-n-butyl (DnBP), diisobutyl (DiBP), di(2-ethylhexyl) (DEHP) and diisononyl (DiNP) phthalates. We calculated the molar sums of DEHP, DiNP, and all AAP metabolites. We used group-based trajectory models (GBTMs) to identify subgroups of boys who followed similar pubertal trajectories from ages 8-19 years based on annual TV. We used multinomial and ordinal regression models to evaluate whether prepubertal log-transformed phthalate metabolite concentrations were associated with slower or faster pubertal progression trajectories, adjusting for covariates.

RESULTS

304 boys contributed a total of 752 prepubertal urine samples (median 2, range: 1-6) for creation of individual pools. The median length of follow-up was 10.0 years; 79% of boys were followed beyond age 15. We identified three pubertal progression groups: slower (34%), moderate (43%), and faster (23%) progression. A standard deviation increase in urinary log-monobenzyl phthalate (MBzP) concentrations was associated with higher adjusted odds of being in the slow versus faster pubertal progression trajectory (aOR 1.47, 95% CI 1.06-2.04). None of the other phthalate metabolites were associated with pubertal progression.

CONCLUSIONS

On average, boys with higher concentrations of prepubertal urinary MBzP had a slower tempo of pubertal progression, perhaps attributable to the disruption of androgen-dependent biological pathways.

The effects of estrogen induction therapy on pubertal presentations in turner syndrome patients

OBJECTIVE

In this study, we investigated various pubertal presentations and progressions before and after estrogen induction therapy and the correlations with Turner syndrome karyotypes.

MATERIALS AND METHODS

We reviewed the medical records of patients with Turner syndrome diagnosed before the age of 18 years between 2000 and 2019. Sixty-six patients were enrolled and distributed into 45,X monosomy group, X chromosome structural abnormalities group and X mosaicism group. The pubertal presentations were classified into spontaneous puberty, arrested puberty and no spontaneous puberty. All patients' karyotypes, pubertal progressions and laboratory data were collected and analyzed.

RESULTS

The karyotypes were highly correlated with pubertal presentations. No spontaneous puberty was noticed in 58.3% 45,X monosomy patients, 50% patients with X chromosome structural abnormalities had arrested puberty, whereas 70% patients with X mosaicism had spontaneous puberty. Estrogen induction therapy in patients with no spontaneous puberty could induce puberty and the tempo of puberty may approximate to the spontaneous puberty group (median, 2.3 vs. 2.2 years, P = 0.95). In both interventional groups, the FSH level was distinguishable before treatment (median, 65.1 vs. 100.4 mIU/mL, P = 0.02). After long term estrogen therapy, the FSH could be suppressed to similar level in both interventional groups (median, 37.5 vs 34.5 mIU/mL, P = 0.84). Neither LH nor E2 level provided valuable information before and after treatment.

CONCLUSION

The karyotypes were highly correlated with pubertal presentations at Turner syndrome patients. The integrity of 2nd X chromosome plays an important role. Low dose estrogen could mimic the tempo of puberty even delay induction age at Taiwan. The FSH data could provide predictive information of pubertal induction for both interventional groups.

Blood lead levels and timing of male sexual maturity: A longitudinal study of Russian boys

BACKGROUND

Higher blood lead levels (BLLs) have been linked to neurologic deficits and impaired growth, but few studies have evaluated their association with timing of sexual maturity or pubertal progression in boys.

METHODS

In a longitudinal cohort of Russian boys enrolled at age 8-9 and followed to adulthood, BLLs were measured at study entry, and pubertal staging (genitalia and pubic hair) and testicular volume (TV) measurements were obtained annually. We used interval-censored regression models to estimate differences between boys with higher BLL (≥5 μg/dL) and lower BLL in mean ages at sexual maturity (genitalia stage 5, pubic hair stage 5, or TV ≥ 20 mL) and duration of pubertal progression (onset to maturity), adjusting for potential confounders. Mediation analyses were conducted to quantify the percent of lead's effect attributable to its association with reduced somatic growth.

RESULTS

Among 481 evaluable boys, 28% had BLL ≥ 5 μg/dL. Adjusted mean ages at sexual maturity were 14.7 years for genitalia, 16.1 for pubic hair, and 13.9 for TV. In adjusted models, boys with BLLs ≥5 μg/dL had later maturity than those with lower levels by 4-5 months depending on pubertal indicator. In mediation analyses, height and body mass index at age 11 accounted for 40-71% of the shift in age at maturity for boys with higher compared to lower BLLs. Higher BLLs were not associated with pace of pubertal progression.

CONCLUSIONS

Higher lead levels were associated with later attainment of sexual maturity in males, but not with the duration of pubertal progression. A high proportion of the delay in sexual maturity for boys with higher as compared to lower BLL was shown to be attributable to mediating effects of BLL on reduced growth.