Geographic location in the UK may influence human biochemistry and health outcomes due to environmental factors. This can provide benefits in terms of vitamin D status but may also pose a risk due to higher skin cancer

Introduction There is evidence that populations living close to the coast have improved health and wellbeing. Coastal environments are linked to promotion of physical activity through provision of safe, opportune, aesthetic and accessible spaces for recreation. Exposure to coastal environments may also reduce stress and induce positive mood. In addition to these processes we hypothesised that coastal climate may influence the vitamin D status of residents and thus partly explain benefits to health. Materials and Methods Ecological and cross-sectional analyses were designed to elucidate the connection between coastal residence and vitamin D status. We divided residential data, from developed land use areas and the Lower Super Output Areas of the 1958 Birth Cohort participants, into the following coastal bands: <1km, 1-5km, 5-20km, 20-50km and over 50km. In the ecological analysis we used a multiple regression model to describe the relationship between UVvitd and coastal proximity adjusted for latitude. Subsequently, using the residential information of the participants of the 1958 Birth Cohort we developed a multiple regression model to understand the relationship between serum 25(OH)D (a marker of vitamin D status) and coastal proximity adjusted for several factors related to vitamin D status (e.g. diet, outdoor activity). Results We found that coastal proximity was associated with solar irradiance; a 99.6 (96.1-103.3) J/m2/day regression coefficient was observed for settlements <1 km from the coast compared with those above 50 km. This relationship was modified by latitude with lower latitude exhibiting a greater effect. Individuals living in the <1 km coastal category had on average a 4 nmol/l higher vitamin D status compared to those living inland. Conclusion Geographic location in the UK may influence human biochemistry and health outcomes due to environmental factors. This can provide benefits in terms of vitamin D status but may also pose a risk due to higher skin cancer rates. We provide further evidence in support of the claim that coastal environments can provide opportunities for health and wellbeing. Suggested Reviewers: Kaye Brock [email protected] Brock is an experienced nutritional epidemiologist. Brock et al have investigated multiple environmental factors on the vitamin D status of Finnish men. Elina Hypponen [email protected] Hypponen has worked extensively with the 1958 Birth Cohort and is an expert on vitamin D and health, publishing frequently in this field Robyn Lucas [email protected] Lucas is an expert in the field of UV exposure, vitamin D and public health. Lucas et al have highlighted the multifactorial contribution of environment, genes and other factors to the vitamin D status of healthy adults.