Increasing incidence of club foot with higher population density: Incidence and geographical variation in Denmark over a 16–year period—an epidemiological study of 936,525 births

Abstract

Background The occurrence of club foot (CF) varies between countries and populations, and may be related to endogenous and exogenous factors. We analyzed the occurrence of CF in a whole country over a long period of time (16 years). Methods Patients born in Denmark with a foot deformity 1978-93 were identified from the National Patient Register and the Register of Inborn Malformations. The records for each patient were studied in the hospital departments to establish the diagnoses and to obtain additional information. Demographic data were obtained from the Danish National Demographical Institute and from the Danish Population Register.Results The incidence of isolated CF was 1.2/1,000 live births. It increased significantly during the study period, and the incidence of CF and the standardized morbidity ratio for CF were significantly positively correlated to population densities in the counties and the districts. There was no significant increase in the relative proportion of children with CF born to non-Scandinavian parents during the period.Interpretation The increasing incidence of isolated CF with higher population density indicates that there may be exogenous factors that are pathogenic.

Multistate study of the epidemiology of clubfoot

“…This trend was not driven by one specific program; instead, six of the surveillance programs reported slight increases in clubfoot over the five-year period. These findings were inconsistent with those of a previous report of a decline in prevalence from 1968 through 2003 (Correa et al, 2007), but were consistent instead with findings of increasing or unchanging prevalence (Krogsgaard et al, 2006). The cause of the observed trend is unclear, but monitoring the prevalence of clubfoot and its risk factors warrants further attention.…”

“…The change in the association between maternal age and clubfoot was largely influenced with the addition of maternal education and parity to the model, indicating that education and parity are stronger risk factors for clubfoot than maternal age. Environmental exposures that might have been mediated by socioeconomic status, such as urban residence, are also possible explanations in the pathogenesis of clubfoot (Krogsgaard et al, 2006). Maternal smoking during pregnancy has been one of the more widely studied risk factors for clubfoot.…”

Club foot in association with the 22q11.2 deletion syndrome: An observational study

“…The majority (74%) of the CHOP cohort is Caucasian and since the prevalence of club foot within the general Caucasian population is ~1:1,000 patients, the prevalence of club foot occurs approximately 30 times more often within 22q11.2DS as compared to the general Caucasian population. Moreover, the bilateral:unilateral and male:female ratio are comparable with the general population (Krogsgaard et al, 2006; Parker et al, 2009; Stone et al, 2017; Werler et al, 2013). Last, we did not find a relation between the presence of club foot and the presence of a CHD and/or a cleft palate.…”

“…The prevalence of congenital isolated club foot in the general population differs among multiple ethnic populations, but is approximately 1.2–6 per 1,000 individuals. Within the group of patients with isolated club foot the male:female ratio is 2:1 and half of the patients have a bilateral club foot (Cartlidge, 1983; Krogsgaard et al, 2006; Parker et al, 2009; Stone, Martis, & Crawford, 2017; Werler et al, 2013). In studies on club foot within 22q11.2DS the prevalence ranges from 1.1 to 13.3%, which seems to be higher as compared to the general population (Homans et al, 2017).…”

A population-based case control study of congenital abnormalities and medication use during pregnancy using the Czech National Register of congenital abnormalities

“…The most frequent congenital foot deformity, club foot (1237 of 2589 congenital foot deformity cases in our study) could be influenced by heritability as incidence is different among races and sexes. Krogsgaard et al [11] described that also exogenic factors are pathogenic. In their study, they found increasing incidence of club foot with higher population density.…”