Hallux valgus is far commoner in women – most series have eight or ten women for every man. There may be some selection bias – in particular, women may present more often seeking treatment because women’s shoes are often poor at accommodating deformity. Hallux valgus is also associated with joint laxity, and women’s joints may be laxer than men’s, perhaps because of oestrogens. Shoe wear also has an effect on the development of hallux valgus, and women’s shoes tend to be narrower across the toe-box and to have higher heels, both of which probably have an effect on the development of hallux valgus.
It might be thought that the female predominance is simply genetic, but in fact Coughlin found that men with hallux valgus are more likely to have first degree relatives with the deformity than women. In addition, men more commonly have congruent hallux valgus, with altered DMAA and hallux valgus interphalangeus, than women. Therefore, the genetic component in women is probably more multi-factorial than in men, and may affect different aspects of the deformity, possibly metatarsal shape rather than joint laxity.
There have been a number of studies comparing the prevalence of hallux valgus in shoe-wearing and non-shoe-wearing populations who are otherwise similar. Even in non-shoe-wearing populations, hallux valgus occurs in about 4-5%, and Myerson suggests this represents a minimum susceptibility whatever the environment of the foot. However, in similar, shoe-wearing populations, hallux valgus was 2-3 times commoner. The greater prevalence in women in Western populations may also partly relate to the shape of women’s shoes.