[...]Q: What do 19th century London-dwellers and conservative Muslim women living in 21st century Scandinavia have in common?
A: Both display a tendency toward vitamin D deficiency.
Historical accounts indicate that rickets was common in 19th century English cities, probably because coal smoke was so thick it hid the vitamin D-producing midday sun. (Rickets is a disease in which developing bones soften and curve because they aren't receiving enough calcium, uptake of which into bones requires adequate vitamin D.)
Modern research suggests that the traditional head covering called the hijab leaves Islamic women living in already sun-lacking northern latitudes prone to substantial vitamin D deficiency, which can promote cancer, depression—and osteoporosis.
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