1. Unit for Population‐Based Dermatology Research, St John's Institute of Dermatology King's College London and Guy's and St Thomas' NHS Foundation Trust London UK
2. School of Population Health and Environmental Sciences Research King's College London London UK
3. Department of Epidemiology, Geisel School of Medicine at Dartmouth Dartmouth College Hanover New Hampshire USA
4. Trace Element Analysis Core Laboratory, Department of Earth Sciences Dartmouth College New Hampshire USA
5. Department of Pediatrics & Psychiatry, Children's Hospital at Dartmouth Dartmouth Hitchcock Medical Center Lebanon New Hampshire USA