Did the Little Ice Age (dim sun plus volcanoes) increase rickets in the 1700s?
’The bright sun was extinguish’d’: metabolic health and vitamin D status in a Little Ice Age population (18th–19th c.) in North East England
Frontiers in Environmental Archaeology, 5 November 2026, https://doi.org/10.3389/fearc.2026.1909791
Ellen J. Kendall, Anne Marie Sohler-Snoddy, Ross Kendall, Hannah Koon, Rebecca Gowland, Marie C. Weale, Ian Chaplin, Sophie Edwards
Summary by Claude Opus 5.5 - November 2026
Takeaway: Even a fairly well-off community in North East England (55°N) had widespread childhood vitamin D deficiency in the 1700s, and their teeth show it coming back winter after winter. The authors propose that the Little Ice Age made it worse: low solar activity and repeated volcanic eruptions brought cool, dim summers that kept people indoors and bundled up when skin should be making vitamin D. A reasonable idea, but this study does not test it. (The title quotes Byron's 1816 poem "Darkness," written in the "Year Without a Summer.")
Study type and size: Peer-reviewed bioarchaeology study (observational, no formal statistics) of a Quaker cemetery in North Shields, burials 1711–1829. It combines tooth thin-sections from 21 skeletons (most already published in Snoddy 2024), the burial register (109 people with an estimable birth year), and published rates from other 17th–19th century sites.
Findings:
- 16 of 21 people (76%) had interglobular dentin, poorly mineralized bands linked to low vitamin D while teeth form; 11 had repeated episodes.
- One woman's teeth recorded 18 roughly yearly episodes, from age 1 to 18.
- 28 of 63 children's skeletons (44%) had rickets.
- 87% of births fell in a grand solar minimum, within 10 years after a large eruption, or both.
- Rates across sites did not track latitude, industry or wealth, but sites used mostly before 1800 tended to be worse. A cemetery across the river in South Shields (1816–1855) had no rickets in 90 children.
- The authors conclude the causes are "complex, multiple, synergistic, and specific to time, place, and environment."
What this does NOT show:
- Cause. By my rough check, about 4 in 5 years from 1625 to 1824 fall inside one of the paper's climate windows, so about 82% of births would land in one by chance, versus the 87% reported. The paper makes no such comparison.
- A person-by-person link: none of the 21 sampled skeletons can be matched to a birth year.
- Vitamin D specifically: low calcium intake can cause similar tooth and bone defects.
- A settled answer on latitude: only 3 sites had tooth data. The sunniest, Montreal (45°N), had far fewer repeat episodes (16% of those affected) than Coach Lane (69%) or Wolverhampton (82%), though the authors saw no clear latitude pattern.