Table 3 Multivariable-adjusted regression coefficients for annual age-standardised lung cancer incidence rates per 100 000 men, according to solar UVB irradiance, total cloud cover, anthropogenic aerosol optical depth, and per capita cigarette consumption, and contribution of each covariate to the coefficient of determination, R², 111 countries that reported data on cigarette use, GLOBOCAN, 2002

Variable	Multiple regression coefficient	Standard error		t		p	Contribution to R²
Solar UVB irradiance*	−1.443	0.468	−3.08		0.003		0.04
Total cloud cover†	15.711	7.777	2.02		0.05		0.01
Anthropogenic aerosol‡	19.282	6.782	2.84		0.005		0.02
Cigarette consumption§	0.016	0.002	8.63		<0.001		0.71

R² = 0.78, p<0.001.
*W/m² at vernal equinox, 297–320 nm. Source: Calculated using a standard algorithm from Columbia University for UVB irradiance according to latitude and date.17
†Mean percentage of sky covered with clouds, winter solstice. Source: International Satellite Cloud Climatology Project.15
‡Source: NASA MODIS project.14
§Based on per capita cigarette consumption data from the World Health Organisation, computed as sex-specific cigarette consumption.12