Lead poisoning in new immigrant children from the mainland of China.

Objective: To define the prevalence, severity and risk factors for lead poisoning in new immigrant children from the mainland of China to Hong Kong, China.
Methods: New immigrant children from the mainland of China under 18 years of age were invited to join the study. Their growth parameters and venous blood lead levels (BLL) were measured within 7 days of arrival. Those with elevated BLL i.e. > 10 micrograms/dl (0.48 mumol/L) were assessed for signs, symptoms and risk factors of lead poisoning. Education on the prevention of lead poisoning and follow up BLL measurements were offered until their BLL normalized.
Results: Four hundred and fifty-seven children were recruited. Among them, 18.1% and 2.6% had BLL > 0.48 and 0.71 mumol/L, respectively. None had BLL > 0.96 mumol/L. Possible risk factors included contaminated drinking water (19%), herb ingestion (17.5%), pica, playing in dumping grounds, residing near paint factories or highways, habitual inhalation of car exhaust and cooking with petroleum. Symptoms and signs included abdominal pain, headache, short stature, and learning difficulties but did not correlate with BLL. None required treatment except for counseling on the avoidance of risk factors. About 94.7% showed a reduction in BLL 2-3 months after arrival and before counseling. All had normalized BLL by 9 months except 1 who had an X-ray feature of lead line.
Conclusions: Lead poisoning is common in new immigrant children from the mainland of China. Environmental factors were most important while behavioral factors like regular herb ingestion might have contributed to the persistence of high BLL in the minority.