The trend of lead poisoning rate in Chinese population aged 0-18 years old: a meta-analysis

Background: Childhood lead poisoning is a public health problem gained widely attention for the health damage caused by lead exposure. Pediatrics defines lead poisoning as BLL of or higher than 10 mu g/dL, which leads to harmful effects in nervous system, hematological system and urinary system. This study investigates the percentage of 0-18 year old Chinese population with blood lead level (BLL) >= 10 mu g/dL during 1990-2012 by searching epidemiologic studies from electronic database focused on BLL in mainland China. Methods: Epidemiologic studies about BLL in China mainland between January 1990 and October 2012 were searched from electronic databases including CNKI, CBM disc, Wanfang Data, Pubmed and Medline. Data extraction, data analysis and risk of bias assessments were performed. Results: Fifty-five articles were included in analysis containing 200,002 subjects, covering 19 provinces, autonomous regions and municipalities. The corrected pooled rate by trim and fill method under random effect model was 9 % (95 CI: 6 %, 12 %). The corrected pooled lead poisoning rate by trim and fill method was 28.1 % (95 % CI: 21.6 %, 34.6 %) from data published during 1990-2000, much higher than the rate during 2001-2005 (10.5 %, 95 % CI: 6.4 %, 14.5 %) and the rate during 2006-2012 (5.3 %, 95 % CI: 3.7 %, 7 %). The corrected pooled lead poisoning percentage in eastern zone (4.3 %, 95 % CI: 2 %, 6.6 %) was slightly lower than that in western zone (5.8 %, 95 % CI: 3.2 %, 8.5 %) and much lower than in central zone (8.5 %, 95 % CI: 4.9 %, 12.1 %). The corrected pooled rate of population living around mining area (70 %, 95 % CI: 62.7 %, 77.3 %) was much higher than that of population in urban area (9.6 %, 95 % CI: 7.1 %, 12.1 %), suburban area (23.6 %, 95 % CI: 17 %, 30.3 %), rural area (23.8 %, 95 % CI: 6.7 %, 40.9 %) and industrial area (57.5 %, 95 % CI: 28 %, 86.9 %). In male population, the corrected pooled rate (10 %, 95 % CI: 7 %, 13 %) was slightly higher than that in female population (7.7 %, 95 % CI: 5 %, 10.4 %). Considering different age groups, the lead poisoning prevalence gradually rose with the increase of age and reached peak level at preschool age, then declined slightly with age. Conclusion: This meta-analysis revealed lead exposure situation of Chinese population in recent decades which provide robust evidence for policy making.