[Risk factors linked to the transmission of papilloma virus in the school environment. Alicante, 1999]

Warts transmitted in families and schools: a prospective cohort

BACKGROUND AND OBJECTIVE

Cutaneous warts are common in primary schoolchildren; however, knowledge on the routes of transmission of human papillomavirus (HPV) causing warts is scarce. This study examines the association between the degree of HPV exposure and incidence of warts in primary schoolchildren to support evidence-based recommendations on wart prevention.

METHODS

In this prospective cohort study, the hands and feet of all children in grades 1 to 7 (aged 4-12 years) of 3 Dutch primary schools were inspected for the presence of warts at baseline and after 11 to 18 months of follow-up. Data on the degree of HPV exposure included information obtained from parental questionnaires: preexistent warts, warts in family, prevalence of warts at baseline in the class, and use of public places (eg, swimming pools).

RESULTS

Of the 1134 eligible children, 97% participated; the response rate from parental questionnaires was 77%, and loss to follow-up was 9%. The incidence for developing warts was 29 per 100 person-years at risk (95% confidence interval [CI] 26-32). Children with a white skin type had an increased risk of developing warts (hazard ratio [HR] 2.3, 95% CI 1.3-3.9). Having family members with warts (HR 2.08, 95% CI 1.52-2.86) and wart prevalence in the class (HR 1.20 per 10% increase, 95% CI 1.03-1.41) were independent environmental risk factors.

CONCLUSIONS

The degree of HPV exposure in the family and school class contributes to the development of warts in schoolchildren. Preventive recommendations should focus more on limiting HPV transmission in families and school classes, rather than in public places.

Warts in primary schoolchildren: prevalence and relation with environmental factors

BACKGROUND

Warts are very common in primary schoolchildren. However, knowledge on wart epidemiology and causes of wart transmission is scarce.

OBJECTIVES

To determine the prevalence of warts in primary schoolchildren and to examine the relation with environmental factors in order to provide direction for well-founded recommendations on wart prevention.

METHODS

In this cross-sectional study, the hands and feet of 1465 children aged 4-12 years from four Dutch primary schools were examined for the presence of warts. In addition, the children's parents completed a questionnaire about possible environmental risk factors for warts.

RESULTS

Thirty-three per cent of primary schoolchildren had warts (participation rate 96%). Nine per cent had hand warts, 20% had plantar warts and 4% had both hand and plantar warts. Parental questionnaires (response rate 76%) showed that environmental factors connected to barefoot activities, public showers or swimming pool visits were not related to the presence of warts. An increased risk of the presence of warts was found in children with a family member with warts [odds ratio (OR) 1.9, 95% confidence interval (CI) 1.3-2.6] and in children where there was a high prevalence of warts in the school class (OR per 10% increase in wart prevalence in school class 1.6, 95% CI 1.5-1.8).

CONCLUSIONS

One-third of primary schoolchildren have warts. This study does not find support for generally accepted wart prevention recommendations, such as wearing protective footwear in communal showers and swimming pool changing areas. Rather, recommendations should focus on ways to limit the transmission of wart viruses within families and school classes.