title: [Digit length ratio and male fertility among infertile patients in Ningxia].
abstract: OBJECTIVE
  To investigate the association between the digit length ratio (DLR) and male fertility in Ningxia.
  
  
  METHODS
  Using an electronic sliding caliper, we measured the lengths of the index finger (D2), middle finger (D3), ring finger (D4) and little finger (D5) of both the right and left hand of 136 infertile males in Ningxia, 45 of them with normal and the other 91 with abnormal semen, including 28 cases of oligozoospermia, 10 cases of obstructive azoospermia (OA) and 53 cases of nonobstructive azoospermia (NOA). We calculated the DLRs of D2:D3, D2:D4, D2:D5, D3:D4, D3:D5 and D4:D5 and compared them among different groups.
  
  
  RESULTS
  The mean values of FLR presented a pattern of D2:D3 < D2:D4 < D3:D4 < D2:D5 < D4:D5 in the infertile males. DLRs of D2:D3, D2:D4, D2:D5, D3:D5 and D4:D5 of the right hand were significantly higher in the abnormal than in the normal semen group (t = 2.56, 2.48, 3.57, 2.85, 2.53; P < 0.05); those of D2:D3, D2:D4, D2:D5 and D4:D5 of the right hand presented a pattern of NOA > oligozoospermia > OA > normal semen group, while that of D3:D5 presented a pattern of NOA > OA > oligozoospermia > normal semen group. The NOA group showed a significantly higher DLR of the right hand than the normal semen group in D2:D3, D2:D4, D3:D5 and D4:D5, the oligozoospermia group in D2:D4, D3:D5 and D4:D5, and the OA group in D2:D3 (P < 0.05). The D4:D5 DLR of the right hand was remarkably higher in the Han than in the Hui ethnic group (t = 2.01, P < 0.05).
  
  
  CONCLUSIONS
  Higher DLRs of D2:D3, D2:D4, D2:D5, D3:D5 and D4:D5 of the right hand were associated with lower fertility in infertile males in Ningxia. And the D4:D5 FLRs of the right hand may be different between Hui and Han infertile men in Ningxia.
authors.affiliation: Center of Reproductive Medicine, General Hospital of Ningxia Medical University, Yinchuan, Ningxia 750004, China. zhaojunlii@yahoo.com.cn
authors.forename: Jun-Li
authors.initials: JL
authors.lastname: Zhao
authors.forename: Li
authors.initials: L
authors.lastname: Liu
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.forename: Feng-Hua
authors.initials: FH
authors.lastname: Li
authors.forename: Yin-Yin
authors.initials: YY
authors.lastname: Yuan
authors.forename: Wan-Hong
authors.initials: WH
authors.lastname: Jing
authors.forename: Cai-Yan
authors.initials: CY
authors.lastname: Li
mesh_terms: D000328:Adult; D002681:China / Q000453:epidemiology; D005298:Fertility; D005385:Fingers / Q000033:anatomy & histology*; D006225:Hand / Q000033:anatomy & histology; D006801:Humans; D007248:Infertility, Male / Q000453:epidemiology*; D008297:Male; D055815:Young Adult