“…South-to-north gradients have been identified for a number of diseases or health indicators including multi- ple sclerosis (MS; Hogancamp et al, 1997;Fromont et al, 2010), inflammatory bowel disease (Nerich et al, 2006;Nerich et al, 2010), cardiovascular disease and stroke (Cottel et al, 2000;Morris et al, 2001;Morris et al, 2003), and perinatal mortality (Tromp et al, 2009). However, the assumption is that geographic gradients are underlaid by linked gradients with more plausible association with CHD occurrence.…”