Diet, ageing and genetic factors in the pathogenesis of diverticular disease

Table 2 Observational studies of dietary fiber consumption and DD risk in man

Design	Findings	Comments	Reference
Case control study comparing dietary fiber intake in 100 (symptomatic) DD cases vs 80 age and sex matched controls	Dietary fiber intake significantly higher amongst controls	Study participants were patients hospitalized due to diverticulosis; again symptoms may have influenced their diet	Manousos et al[12]
Prevalence of DD assessed by barium enema in 189 non-vegetarian volunteers vs 55 vegetarians	Diverticular disease was significantly higher in the non- vegetarian group	"Asymptomatic" volunteers recruited prior to diagnosis and grouped based on dietary choices. A potential confounder is a possible causative effect for meat	Gear et al[104]
Case control study comparing dietary fiber intake in 40 (symptomatic) DD cases vs 80 age and sex matched controls	Dietary fiber intake significantly higher amongst controls	Dietary fiber intake was "estimated" by dieticians. Symptomatic DD patients were studied so the symptoms may have influenced their diet	Brodribb et al[62]
"Prospective" case control study. As part of the Health professionals follow up study, 43 881 US men aged 40-75 followed over 6 years, for self reported diagnoses	Dietary fiber intake significantly lower in cases RR = 0.63	The largest and potentially most informative study. Crucially, the participants were not clinically examined for DD prior to the study. So we cannot rule out effects of DD on dietary choices	Aldoori et al[63]
Case control study comparing dietary fiber intake between 86 right-sided DD cases and 106 controls	No relationship between DD and fiber consumption	Only study on right-sided DD, negative finding may indicate either a different etiology or perhaps right-sided DD just has fewer effects that might influence diet choice	Lin et al[64]

RR: Relative risk.