Rural Rickets: Vitamin D Deficiency in a Post‐Medieval Farming Community from the Netherlands

Rickets is caused by vitamin D deficiency as a result of limited exposure to sunlight and inadequate diet. In the 19^th century, rickets was endemic in most northern European cities. In post‐Medieval Netherlands, rickets is documented in low frequencies in a few urban samples, but has not been studied in contemporaneous rural populations. Beemster is a rural farming community in the Netherlands that was established in the 17^th century upon drained land, with the Middenbeemster cemetery in use until 1866 AD. Ninety‐five individuals from the ages of 32 weeks in utero to 15 years were examined for rickets in order to understand factors that can cause vitamin D deficiency in rural, non‐industrialized populations. To identify rickets in the Beemster sample, ten features were scored, with bending deformities of the lower limb and one other feature, or at least three non‐bending features, having to be present in order for diagnosis. Nine individuals (9.5%) had evidence of rickets—a high prevalence, especially for a rural community where ample sunlight was available. The two and three year old Beemster infants were most heavily affected with an age‐specific prevalence of 30.4%. Two three‐month‐old infants also had rickets. Some of the affected may have developed rickets secondarily, as a result of a different illness, but cultural practices including prolonged swaddling, occlusive clothing, and keeping the young indoors, are suggested to have contributed to this high rickets prevalence. Dietary variables including poor weaning foods and common episodes of malnutrition may have also contributed to vitamin D deficiency. This study demonstrates the value of careful analysis of pathological conditions in subadults and highlights that rickets was not only a disease of cities, but affected populations that would appear to have been at low risk, because of maladaptive cultural practices. Copyright © 2013 John Wiley & Sons, Ltd.