BACKGROUND: Ratio of second and fourth digit (2D:4D) is known to be germane in 
analyzing utero concentrations of testosterone and estrogen in human and other 
vertebrates. 2D:4D had been linked to several traits like athletes' abilities, 
reproductive success, risk of cancer and cardiovascular disease (CVD). Metabolic 
syndrome (MetS) is a clustering of several cardiovascular risk factors. Waist 
circumference (WC), neck circumference (NC), body mass index (BMI) and 
waist-to-height ratio (WHtR) are important in measuring MetS. This study 
investigated sexual dimorphism in 2D:4D and its relationship with MetS indices 
and CVD factors among adult residing in Ilorin, North central Nigeria.
MATERIALS AND METHODS: This is a cross-sectional, stratified multi-staged 
sampling study. Participants residing in different neighborhoods were visited at 
home where finger lengths and anthropometric traits were measured. Participants 
include 801 healthy adults aged 18-44 years (56% male) who had been living in 
the area for more than 3 years.
RESULTS: Males showed significantly lower 2D:4D than females (unpaired t-test; t 
[699] = 11.49, P = 0.001). A significant positive correlation was observed in 
MetS markers and 2D:4D. WHtR showed the highest correlation with 2D:4D in male 
(r = 0.461, P ≤ 0.001) and female (r = 0.408, P ≤ 0.001) when compared with BMI, 
NC and WC. All positive correlations recorded in this study were high in male 
and right hand.
CONCLUSION: Our results showed that 2D:4D is sexual dimorphic and right hand 
2D:4D as a predictor of MetS is better. We concluded that 2D:4D is a proxy for 
MetS and CVD risk factors in Ilorin.