Anna S Oberg1, Eduardo Villamor. 1. Department of Epidemiology, Harvard School of Public Health, Boston, MA 02115, USA. oberg@hsph.harvard.edu
Abstract
BACKGROUND: The ratio between the lengths of the second and fourth fingers (digit ratio: 2D : 4D), a purported negative correlate of prenatal androgen exposure, has been inversely related to age at menarche. However, a recent study found high digit ratios in carriers of a single variant in the LIN28B gene, which has been linked to delayed menarche. METHODS: We investigated the association of digit ratio and age at menarche in 299 pre-menarcheal girls aged 5-12 years who participated in a longitudinal cohort study in Bogotá, Colombia. Finger lengths were measured at baseline and the occurrence of menarche was periodically ascertained over a median 32 months of follow-up. We used time-to-event analysis to estimate median ages at menarche as well as hazard ratios for menarche according to tertiles of the digit ratio for each hand. RESULTS: Estimated median age at menarche was lower for girls in the lowest digit ratio tertile of the right hand compared with those in the highest (12.0 vs. 12.3 years; P-value = 0.04). After adjustment for baseline age, height- and body mass index-for-age z-scores, the hazard of menarche was 86% higher in girls of the lowest digit ratio tertile (hazard ratio 1.9 [95% confidence interval 1.2, 2.9]) compared with those in the highest digit ratio tertile of the right hand. No significant associations were found with the left hand. CONCLUSIONS: Digit ratio was positively associated with age at menarche in this longitudinal investigation, consistent with results from a recent gene-linkage study.
BACKGROUND: The ratio between the lengths of the second and fourth fingers (digit ratio: 2D : 4D), a purported negative correlate of prenatal androgen exposure, has been inversely related to age at menarche. However, a recent study found high digit ratios in carriers of a single variant in the LIN28B gene, which has been linked to delayed menarche. METHODS: We investigated the association of digit ratio and age at menarche in 299 pre-menarcheal girls aged 5-12 years who participated in a longitudinal cohort study in Bogotá, Colombia. Finger lengths were measured at baseline and the occurrence of menarche was periodically ascertained over a median 32 months of follow-up. We used time-to-event analysis to estimate median ages at menarche as well as hazard ratios for menarche according to tertiles of the digit ratio for each hand. RESULTS: Estimated median age at menarche was lower for girls in the lowest digit ratio tertile of the right hand compared with those in the highest (12.0 vs. 12.3 years; P-value = 0.04). After adjustment for baseline age, height- and body mass index-for-age z-scores, the hazard of menarche was 86% higher in girls of the lowest digit ratio tertile (hazard ratio 1.9 [95% confidence interval 1.2, 2.9]) compared with those in the highest digit ratio tertile of the right hand. No significant associations were found with the left hand. CONCLUSIONS: Digit ratio was positively associated with age at menarche in this longitudinal investigation, consistent with results from a recent gene-linkage study.
Authors: Nis Brix; Andreas Ernst; Lea L B Lauridsen; Erik T Parner; Jørn Olsen; Tine B Henriksen; Cecilia H Ramlau-Hansen Journal: Am J Epidemiol Date: 2019-01-01 Impact factor: 4.897
Authors: Sana Syed; O Yaw Addo; Vanessa De la Cruz-Góngora; Fayrouz A Sakr Ashour; Thomas R Ziegler; Parminder S Suchdev Journal: Nutrients Date: 2016-06-23 Impact factor: 5.717