This review updates a previous Cochrane Review last updated in October 2016. The objectives were to assess the effects of household interventions intended to prevent or reduce further lead exposure in children, on improvements in cognitive and neurobehavioural development, and reductions in blood lead levels and household dust lead levels.
In March 2020, the review authors searched for randomised controlled trials (RCTs) and quasi-RCTs comparing household educational or environmental interventions, or combinations of these interventions, with no intervention or standard measures.
They included 17 studies (16 RCTs, 1 quasi-RCT), three of which were new to this update. A total of 3282 children under six years of age took part in the studies. Fifteen studies were conducted in North America and the remaining two in Australia and China. Most studies were conducted in areas with low socioeconomic status.
The review authors found that, compared with no intervention:
· education probably has no effect on reducing blood lead levels (5 studies, 815 participants; moderate-certainty evidence) or dust floor levels (2 studies, 318 participants; moderate-certainty evidence)
· dust control measures probably have no effect on:
o cognitive and neurobehavioural outcomes (1 study, 224-302 participants; low-certainty evidence); and
o blood lead levels (4 studies, 565 participants; moderate-certainty evidence).
The evidence on soil abatement or studies assessing a combination of interventions was inconsistent (both very low-certainty evidence). And only one study assessed adverse events. It found no adverse events in the intervention during the eight-year follow-up, but observed two children with adverse events in the control group (1 study, 355 participants; very low-certainty evidence).
The review authors concluded that, based on the available evidence, household educational interventions and environmental (largely dust control) interventions showed no evidence of an effect in reducing children’s blood lead levels. The evidence of the effects of environmental interventions on cognitive and neurobehavioural outcomes and adverse events was uncertain also. Future studies might change this conclusion.
See the full review here.