'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

Introduction The effects of historical industrialization on health are well documented and frequently acknowledged in bioarchaeology, particularly in studies focusing on the health of European or North American populations of the 17th-19th centuries. Specifically, the negative impacts of coal burning and factory pollution on air quality and UV exposure are commonly cited in bioarchaeological research as primary influences in vitamin D deficiencies in historical industrialized populations. Less frequently considered are the potential health impacts of co-occurring climatic phenomena associated with changes in solar or volcanic activity, such as those that occurred during the Little Ice Age (LIA). Methods We assessed childhood vitamin D deficiency (VDD) and the role of climate factors in human health in an 18th-19th century Quaker cemetery in North East England through multiple lines of evidence. The burial register for Coach Lane, North Shields (AD 1711-1829) was analyzed to estimate demographic and temporal features of the site. Register data were aligned with environmental information for the period, along with dental histological ( n = 30) evidence of disordered mineral metabolism (DMM) and skeletal evidence for VDD. These data were contextualized and compared to results for other contemporaneous European sites from industrial and non-industrial environments and differing latitudes. Results Results for dental histology indicated a population with high levels of interglobular dentin (IGD), including annually recurring bands in some individuals. These indicated a seasonal component and occurred at ages ranging from early life to early adulthood. Analysis of burial register data for Coach Lane revealed a population largely born between the 1620s and 1810s, with most age-estimable individuals born during periods of reduced solar irradiance and temperature associated with solar minima and volcanic activity during the LIA. Wider comparative northern hemisphere dental and skeletal data for prevalence of DMM were not clearly associated with any single feature of industrialization, latitude, urbanization, or socioeconomic status. However, sites with a substantial component of earlier burials (prior to 1800), tended to exhibit higher prevalence of skeletal or dental DMM. Discussion In terms of the chronology and prevalence of skeletal and dental DMM lesions at Coach Lane, inclusion of previously underexplored climate factors during the LIA offers a more complete framework and new insights for understanding the interplay between likely anthropogenic, geographic, and climatic factors in VDD during industrialization. Despite the emphasis put on industrialization and latitude as primary drivers of VDD during the 18th and 19th centuries, in wider comparative data we do not find clear evidence of disparities in prevalence of DMM between pre-industrial, industrializing, or industrial populations, or a pattern of increasing prevalence with latitude, differing socioeconomic status or urbanization. However, it is likely that these factors all play dynamic and variable roles, with greater importance of some factors at some times than others. We suggest that the causes of VDD are complex, multiple, synergistic, and specific to time, place, and environment. Bioarchaeologists should consider climatological evidence as an essential part of environmental context for interpretation of skeletal health.