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Anogenital distance from birth to 2 years: a population study.

Thankamony A, Ong KK, Dunger DB, Acerini CL, Hughes IA - Environ. Health Perspect. (2009)

Bottom Line: Anogenital distance (AGD) is sexually dimorphic in rodents and humans, being 2- to 2.5-fold greater in males.It is a reliable marker of androgen and antiandrogen effects in rodent reproductive toxicologic studies.The availability of normative data provides a means of utilizing this biological marker of androgen action in population studies of the effects of environmental chemicals on genital development.

View Article: PubMed Central - PubMed

Affiliation: Department of Paediatrics, University of Cambridge, Cambridge, United Kingdom.

ABSTRACT

Background: Anogenital distance (AGD) is sexually dimorphic in rodents and humans, being 2- to 2.5-fold greater in males. It is a reliable marker of androgen and antiandrogen effects in rodent reproductive toxicologic studies. Data on AGD in humans are sparse, with no longitudinal data collected during infancy.

Objective: This study was designed to determine AGD from birth to 2 years in males and females and relate this to other anthropometric measures.

Materials and methods: Infants were recruited from the Cambridge Baby Growth Study. AGD was measured from the center of the anus to the base of the scrotum in males and to the posterior fourchette in females. Measurements were performed at birth and at 3, 12, 18, and 24 months of age.

Results: Data included 2,168 longitudinal AGD measurements from 463 male and 426 female full-term infants (median = 2 measurements per infant). Mean AGD (+/- SD) at birth was 19.8 +/- 6.1 mm in males and 9.1 +/- 2.8 mm in females (p < 0.0001). AGD increased up to 12 months in both sexes and in a sex-dimorphic pattern. AGD was positively correlated with penile length at birth (r = 0.18, p = 0.003) and the increase in AGD from birth to 3 months was correlated with penile growth (r = 0.20, p = 0.001).

Conclusion: We report novel, longitudinal data for AGD during infancy in a large U.K. birth cohort. AGD was sex dimorphic at all ages studied. The availability of normative data provides a means of utilizing this biological marker of androgen action in population studies of the effects of environmental chemicals on genital development.

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Mean ± 95% CI AGD measurements in males and females from birth to 2 years of age.
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f2-ehp-117-1786: Mean ± 95% CI AGD measurements in males and females from birth to 2 years of age.

Mentions: Measurements of AGD were obtained from 2,168 visits in 889 infants [median = 2 (range, 1–5) measurements per infant] (Table 2). Males had a greater AGD than did females at birth and at all other time points (p < 0.0001) (Figure 2). At birth, mean AGD in males was approximately 2-fold higher than in females, and this difference persisted to the same extent at all stages of the study. In both sexes, AGD increased rapidly in the first 12 months of life and then gradually plateaued. Figure 3 shows this trend as the distribution of the measurements superimposed on smoothed centile lines. Analysis of longitudinal changes in AGD showed that no further rise in AGD after 18 months of age (Table 3). AGD at birth was associated with subsequent AGD measurements at ages 3, 12, and 24 months in males, but only at 3 months of age in females (Table 4).


Anogenital distance from birth to 2 years: a population study.

Thankamony A, Ong KK, Dunger DB, Acerini CL, Hughes IA - Environ. Health Perspect. (2009)

Mean ± 95% CI AGD measurements in males and females from birth to 2 years of age.
© Copyright Policy - public-domain
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2801188&req=5

f2-ehp-117-1786: Mean ± 95% CI AGD measurements in males and females from birth to 2 years of age.
Mentions: Measurements of AGD were obtained from 2,168 visits in 889 infants [median = 2 (range, 1–5) measurements per infant] (Table 2). Males had a greater AGD than did females at birth and at all other time points (p < 0.0001) (Figure 2). At birth, mean AGD in males was approximately 2-fold higher than in females, and this difference persisted to the same extent at all stages of the study. In both sexes, AGD increased rapidly in the first 12 months of life and then gradually plateaued. Figure 3 shows this trend as the distribution of the measurements superimposed on smoothed centile lines. Analysis of longitudinal changes in AGD showed that no further rise in AGD after 18 months of age (Table 3). AGD at birth was associated with subsequent AGD measurements at ages 3, 12, and 24 months in males, but only at 3 months of age in females (Table 4).

Bottom Line: Anogenital distance (AGD) is sexually dimorphic in rodents and humans, being 2- to 2.5-fold greater in males.It is a reliable marker of androgen and antiandrogen effects in rodent reproductive toxicologic studies.The availability of normative data provides a means of utilizing this biological marker of androgen action in population studies of the effects of environmental chemicals on genital development.

View Article: PubMed Central - PubMed

Affiliation: Department of Paediatrics, University of Cambridge, Cambridge, United Kingdom.

ABSTRACT

Background: Anogenital distance (AGD) is sexually dimorphic in rodents and humans, being 2- to 2.5-fold greater in males. It is a reliable marker of androgen and antiandrogen effects in rodent reproductive toxicologic studies. Data on AGD in humans are sparse, with no longitudinal data collected during infancy.

Objective: This study was designed to determine AGD from birth to 2 years in males and females and relate this to other anthropometric measures.

Materials and methods: Infants were recruited from the Cambridge Baby Growth Study. AGD was measured from the center of the anus to the base of the scrotum in males and to the posterior fourchette in females. Measurements were performed at birth and at 3, 12, 18, and 24 months of age.

Results: Data included 2,168 longitudinal AGD measurements from 463 male and 426 female full-term infants (median = 2 measurements per infant). Mean AGD (+/- SD) at birth was 19.8 +/- 6.1 mm in males and 9.1 +/- 2.8 mm in females (p < 0.0001). AGD increased up to 12 months in both sexes and in a sex-dimorphic pattern. AGD was positively correlated with penile length at birth (r = 0.18, p = 0.003) and the increase in AGD from birth to 3 months was correlated with penile growth (r = 0.20, p = 0.001).

Conclusion: We report novel, longitudinal data for AGD during infancy in a large U.K. birth cohort. AGD was sex dimorphic at all ages studied. The availability of normative data provides a means of utilizing this biological marker of androgen action in population studies of the effects of environmental chemicals on genital development.

Show MeSH