A Prospective Longitudinal Cohort to Investigate the Effects of Early Life Giardiasis on Growth and All Cause Diarrhea

Abstract

Background: Growth stunting in children under 2 years of age in low-income countries is common. Giardia is a ubiquitous pathogen in this age group but studies investigating Giardia's effect on both growth and diarrhea have produced conflicting results.

Methods: We conducted a prospective longitudinal birth cohort study in Dhaka, Bangladesh, with monthly Giardia and continuous diarrheal surveillance.

Results: 629 children were enrolled within the first 72 hours of life, and 445 completed 2 years of the study. 12% of children were stunted at birth with 57% stunted by 2 years. 7% of children had a Giardia positive surveillance stool in the first 6 months of life, whereas 74% had a positive stool by 2 years. The median time to first Giardia positive surveillance stool was 17 months. Presence of Giardia in a monthly surveillance stool within the first 6 months of life decreased length-for-age Z score at 2 years by 0.4 (95% confidence interval, -.80 to -.001; P value .05) whereas total number of Giardia positive months over the 2-year period of observation did not. Neither variable was associated with weight-for-age Z score at 2 years. In our model to examine predictors of diarrhea only exclusive breastfeeding was significantly associated with decreased diarrhea (P value <.001). Concomitant giardiasis was neither a risk factor nor protective.

Conclusions: Early life Giardia was a risk factor for stunting at age 2 but not poor weight gain. Presence of Giardia neither increased nor decreased odds of acute all cause diarrhea.

Keywords: Giardia; diarrhea; growth; low-income countries; stunting.

Figure 1.

Survival plots of presence of Giardia in monthly surveillance stool over the first 2 years of life in urban Bangladeshi infants. Giardia was ubiquitous in children in Dhaka, Bangladesh, with the median time to first Giardia positive surveillance stool at 17 months. For second and third positive surveillance stools the median survival time was 1 and 2 months after initial infection, respectively. 7% of children had a Giardia positive surveillance stool in the first 6 months of life. By 2 years of age 74% of our cohort had at least 1 Giardia positive surveillance stool. 64% had at least 2 positive monthly stools, and 55% had at least 3.