To investigate associations between ethnicity, age and sex and the risk, colon distribution and density scores of diverticular disease (DD). Barium enemas were examined in 1000 patients: 410 male, 590 female; 760 whites, 62 Asians, 44 black africans (BAs), and 134 other blacks (OBs). Risks and diverticula density of left-sided DD (LSDD) and right-sided-component DD (RSCDD = right-sided DD + right and left DD + Pan-DD) were compared using logistic regression. Four hundred and forty-seven patients had DD (322 LSDD and 125 RSCDD). Adjusted risks: (1) LSDD: each year increase in age increased the odds by 6% (95% CI: 5-8, SE: 0.8%, P < 0.001); Asians: odds ratio (OR): 0.23 (95% CI: 0.10-0.53, SE: 0.1, P ≤ 0.001) and OBs: OR: 0.25 (95% CI: 0.14-0.43, SE: 0.07, P ≤ 0.001) appeared protected vs Whites; (2) RSCDD: each year increase in age increased the odds by 4% (95% CI: 2-6, SE: 1%, P < 0.001); females were 0.60 times (95% CI: 0.40-0.90, SE: 0.12, P = 0.01) less likely than males to have RSCDD; BAs were 3.51 times (95% CI: 1.70-7.24, SE: 1.30, P < 0.001) more likely than Whites to have RSCDD; and (3) DD density scores: each year increase in age increased the odds of high-density scores by 4% (95% CI: 1-6, SE: 1%, P < 0.001); RSCDD was 2.77 times (95% CI: 1.39-3.32, SE: 0.67, P < 0.001) more likely to be of high density than LSDD. No further significant differences were found in the adjusted models. Right colonic DD might be more common and has higher diverticula density in the west than previously reported. BAs appear predisposed to DD, whereas other ethnic differences appear conserved following migration.