↵1-150 Origin was characterised as northern European if the death certificate identified national origin as British, Irish, German, Scandinavian, Polish, or other northern European.

↵1-151 Residence at time of death. Levels of sun exposure were categorised based on annual mean daily solar radiation reported by Garlandet al 19 for state reported as residence. Residence was sometimes outside the 24 states in which deaths occurred. Low=generally included states falling within the solar radiation contour lines for annual mean daily solar radiation <350 gm-cal/cm2 and included the following states and other areas: Alaska, Connecticut, Maine, Massachusetts, Michigan, Minnesota, New Hampshire, New York, Ohio, Oregon, Pennsylvania, Rhode Island,Vermont, Washington, Wisconsin, Canada; moderate=>350–400 gm-cal/cm2 and included Arkansas, Delaware, District of Columbia, Idaho, Illinois, Indiana, Iowa,Kansas, Kentucky, Maryland, Missouri, Montana,Nebraska, New Jersey, North Carolina, North Dakota, South Dakota, Tennessee, Virginia,and West Virginia; and high=>400 gm-cal/cm2 and included Alabama, Arizona, California, Colorado, Florida,Georgia, Hawaii, Louisiana, Mississippi,Nevada, New Mexico, Oklahoma, South Carolina, Texas, Utah, Wyoming, Puerto Rico, Virgin Islands, Guam, Cuba, and Mexico. (States in italics are the 24 states that form the mortality database.)

↵1-152 Other included homemakers, retirees, students, volunteers, and those with unknown or no occupation.

↵1-153 Residence sunlight (lifetime) included only those whose residential solar radiation was the same at birth and at death as already defined.

↵1-154 Occupational analysis was limited to those subjects whose usual occupation was classified as highly or moderately active to exclude those whose indoor jobs reflected restricted job options due to the disabilities of their disease. Homemakers were also excluded.