The 2D:4D digit ratio is not a useful marker for prenatal famine exposure: Evidence from the Dutch hunger winter families study

Abstract

Digit lengths, and in particular the ratio of the 2nd (2D) to 4th (4D) digit (2D:4D), are stable in adulthood and have been linked to characteristics thought to have developmental origins, but little research has focused on early life determinants of these measures. We examined whether exposure to acute famine during specific periods of gestation was associated with 2D, 4D or the 2D:4D ratio. We studied men and women (1) born in one of three hospitals in western Netherlands whose mothers were exposed to a limited period of famine immediately prior to or during the pregnancy (n = 337); (2) born in the same hospitals to mothers not exposed to famine during the pregnancy (n = 271) or same-sex siblings of individuals in Groups 1 and 2 (n = 295). We measured 2D and 4D on both hands using calipers and computed the 2D:4D ratio. Mean 2D and 4D lengths were 73.5 (SD 5.1) and 75.0 (5.4) mm, respectively. The 2D:4D ratio was 0.981 (SD 0.030). Both 2D and 4D were associated with male gender and height (all P < 0.001), and weakly with BMI. The 2D:4D ratio was 0.0070 (95% confidence interval 0.0017, 0.0123) lower among males as compared with females, and was not significantly associated with height (0.0002 per cm; 95% -0.0001, 0.0005). The 2D:4D ratio was not significantly associated with exposure to famine, overall (-0.0010, 95% CI 0.0030, 0.0050) or within any period of gestation. The 2D:4D ratio is not significantly affected by prenatal exposure to famine and therefore is not a useful marker for generalized prenatal undernutrition.