INITIATION OF FOOD SUPPLEMENTS AND STOPPING OF BREAST-FEEDING AS DETERMINANTS OF WEANLING SHIGELLOSIS

The association between the period elapsed since weaning and the risk of shigellosis was assessed between 1 November 1987 and 30 November 19 89 for a cohort of 1085 Bangladeshi children aged < 3 years. The child ren were followed for 1 month after exposure to Shigella spp. in their residential neighbourhoods, and the 268 who developed microbiological ly confirmed (n = 118) or clinically presumptive (n = 150) shigellosis were compared with the 817 control children who did not develop eithe r syndrome. No increase in risk was noted among breast-fed infants who received food supplements within the previous 3 months compared with those who had received supplements for longer (adjusted odds ratio (OR ) = 1.2; 95% confidence interval (CI) = 0.4-3.0). However, compared wi th breast-fed children, non-breast-fed children had an increased risk (adjusted OR = 2.0; 95% CI = 1.3-2.9; P < 0.001), which was largely at tributable to a substantially increased risk in the 3 months after sto pping breast-feeding (adjusted OR = 6.6; 95% CI = 2.9-14.6; P < 0.001) . The early post-cessation risk was equivalent for confirmed and presu mptive shigellosis, but was particularly pronounced among the severely malnourished (adjusted OR = 10.2; 95% CI = 3.1-33.3; P < 0.001). This complex temporal pattern of risk highlights the need for precise defi nitions of weaning to facilitate identification of children at high ri sk for invasive diarrhoeal syndromes.