Table 4.

Prevalence of polydactyly and syndactyly by residence

Types	Urban (N: 342,178)		Rural (N: 505,577)		OR(95%CI) (Reference: rural)
	n	Prevalence (‰,95%CI)	n	Prevalence (‰,95%CI)
Polydactyly	912	2.67(2.49–2.84)	976	1.93(1.81–2.05)	1.38(1.26–1.51)
Hand polydactyly	776	2.27(2.11–2.43)	821	1.62(1.51–1.73)	1.40(1.27–1.54)
Foot polydactyly	158	0.46(0.39–0.53)	185	0.37(0.31–0.42)	1.26(1.02–1.56)
Syndactyly	312	0.91(0.81–1.01)	314	0.62(0.55–0.69)	1.47(1.26–1.72)
Hand syndactyly	171	0.50(0.42–0.57)	171	0.34(0.29–0.39)	1.48(1.20–1.83)
Foot syndactyly	154	0.45(0.38–0.52)	166	0.33(0.28–0.38)	1.37(1.10–1.71)

Abbreviations N = number of births; CI = confidence interval; OR = odds ratio