Adverse health effects of child labor: high exposure to chromium and oxidative DNA damage in children manufacturing surgical instruments.
BACKGROUND
A considerable part of the worldwide production of surgical instruments takes place in Sialkot, Pakistan. Many children work in hazardous conditions in this industry.


OBJECTIVE
We investigated exposure to metals and possible health effects among children working in surgical instruments manufacturing units compared with schoolchildren from the same city.


METHODS
In a cross-sectional study we studied a convenience sample of 104 male children (10-14 years of age) working in surgical instruments manufacturing units and 75 male children of similar age from a school in Sialkot, Pakistan. A respiratory questionnaire was administered, spirometry was performed, and blood pressure was measured. In a spot urine sample, concentrations of metals were measured by inductively coupled plasma mass spectrometry and 8-hydroxydeoxyguanosine (8OHdG, reflecting oxidative DNA damage) by ELISA.


RESULTS
The working children reported more asthma (10% vs. 0%; p = 0.005) and dry cough at night (36% vs. 20%; p = 0.02) than did the schoolchildren, but there were no significant differences in pulmonary function or blood pressure. The urinary concentration of chromium was 35 times higher in working children [geometric mean, 23.0 µg/L; 25th-75th percentile, 8.38-58.6] than in schoolchildren [0.66 µg/L; 0.38-1.09)], and largely in excess of the occupational Biological Exposure Index for adult workers (25 µg/L). Urinary 8-OHdG concentrations were not significantly higher in working children than in schoolchildren (19.3 vs. 17.6 µg/g creatinine, p = 0.4), but were significantly correlated with urinary nickel (r = 0.41; p < 0.0001) and with a composite index of metal exposure (r = 0.46; p < 0.0001).


CONCLUSIONS
Children working in the surgical instruments manufacturing industry had substantial exposure to several metals, especially chromium and nickel, which are established carcinogens. Exposure to nickel was associated with evidence of increased oxidative DNA damage.
Lung Toxicology Research Unit, Department of Public Health, KU Leuven, Leuven, Belgium.
Muhammad
M
Sughis
Tim S
TS
Nawrot
Vincent
V
Haufroid
Benoit
B
Nemery
D000080242:8-Hydroxy-2'-Deoxyguanosine; D000293:Adolescent; D000395:Air Pollutants, Occupational / Q000633:toxicity* / Q000652:urine; D015415:Biomarkers / Q000652:urine; D001794:Blood Pressure / Q000187:drug effects*; D002273:Carcinogens / Q000032:analysis / Q000633:toxicity; D002648:Child; D002857:Chromium / Q000633:toxicity* / Q000652:urine; D003430:Cross-Sectional Studies; D004249:DNA Damage / Q000187:drug effects*; D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000652:urine; D004784:Environmental Monitoring; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007221:Industry; D008297:Male; D013058:Mass Spectrometry; D009532:Nickel / Q000633:toxicity / Q000652:urine; D016273:Occupational Exposure; D018384:Oxidative Stress / Q000187:drug effects; D010154:Pakistan / Q000453:epidemiology; D012129:Respiratory Function Tests; D012140:Respiratory Tract Diseases / Q000139:chemically induced* / Q000453:epidemiology; D012621:Seasons; D013147:Spirometry; D013525:Surgical Instruments; D011795:Surveys and Questionnaires
D000395:Air Pollutants, Occupational; D015415:Biomarkers; D002273:Carcinogens; D002857:Chromium; D009532:Nickel; D000080242:8-Hydroxy-2'-Deoxyguanosine; D003849:Deoxyguanosine