Blood lead level in the US population: analysis of the US National Health Nutrition Examination Survey 1999-2012

Abstract

OBJECTIVE: Blood lead level is associated with increased mortality. Therefore, we analysed the updated trends in blood lead level in the US population. METHODS: Data were extracted from the US National Health and Nutrition Examination Survey (NHANES) in 1999 to 2012. For inclusion, participants must include blood lead measurements in the record. They were stratified according to sampling year and age. Data were analysed using SPSS version 22 complex sample module. RESULTS: There were 7970, 8946, 8373, 8407, 8266, 8793, and 7920 participants in NHANES 1999-2000, 2001-2002, 2003-2004, 2005-2006, 2007-2008, 2009-2010, and 2011-2012, respectively. Blood lead levels were (geometric mean [95% confidence interval]) 1.77 [1.72-1.81], 1.57 [1.54-1.61], 1.52 [1.48-1.55], 1.41 [1.38-1.44], 1.38 [1.35-1.41], 1.23 [1.21-1.25], and 1.09 [1.06-1.21] for adults aged 20 years or above, and 1.43 [1.39-1.47], 1.16 [1.13-1.19], 1.18 [1.15-1.21], 0.99 [0.96-1.01], 0.98 [0.96-1.01], 0.81[0.80-0.83], 0.66 [0.64-0.68] for children, respectively. Both decreasing trends were significant (P < 02001). Compared to children aged 7 years or above, children aged 6 years or below had significant higher blood lead levels (1999-2000: 1.24 [1.20-1.28] vs 2.08 [2.01-2.26]; 2001-2002: 1.03 [1.00-1.06] vs 1.65 [1.57-1.73]; 2003-2004: 1.03 [1.01-1.06] vs 1.69 [1.61-1.78]; 2005-2006: 0.86 [0.84-0.88] vs 1.41 [1.35-1.48]; 2007-2008: 0.85 [0.83-0.88] vs 1.46 [1.40-1.54]; 2009-2010: 0.72 [0.70-0.74] vs 1.15 [1.10-1.19]; 2011-2012: 0.59 [0.57-0.61] vs 0.93 [0.88- 0.99]; P < 0.001). CONCLUSION: There is continuous decreasing trend in blood lead level in the US population during the period 1999-2012. The blood lead level in children aged 6 years or below is of concern.