Prenatal lead exposure increases blood pressure in female offspring?

Epidummyologists may have discovered another non-effect.

Here’s the study summary:

Objectives: We investigated the relationship of prenatal lead exposure and blood pressure (BP) in 7-15 year old boys and girls.

Methods: We evaluated 457 mother-child pairs, originally recruited for an environmental birth cohort study between 1994 and 2003 in Mexico City, at a follow-up visit in 2008-2010. Prenatal lead exposure was assessed by measurement of maternal tibia and patella lead using in vivo K-x-ray fluorescence and cord blood lead using atomic absorption spectrometry. BP was measured by mercury sphygmomanometer with appropriate-size cuffs.

Results: Adjusting for relevant covariates, maternal tibia lead was significantly associated with increases in systolic BP (SBP) and diastolic BP (DBP) in girls, but not in boys (p-interaction with sex = 0.025 and 0.007 for SBP and DBP, respectively). Among girls, an interquartile range increase in tibia lead (13 μg/g) was associated with 2.11 (95% CI: 0.69-3.52) mm Hg and 1.60 (95% CI: 0.28-2.91) mm Hg increases in SBP and DBP, respectively. Neither patella nor cord lead was associated with offspring BP.

Conclusions: Maternal tibia lead, which reflects cumulative environmental lead exposure and a source of exposure to the fetus, is a predisposing factor to higher BP in female, but not male, offspring. Sex-specific adaptive responses to lead toxicity during early life development may explain these differences.

We dismiss any discussion of “lead toxicity”, here, because none is shown:

  1. There were no clinical health effects from lead exposure reported in this study;
  2. 1-2 mm Hg changes in blood pressure are meaningless, even in the worst case exposure;
  3. This population of kids had normal blood pressure on average.

The good news is that this study confirms our hypothesis that public health research has devolved into the quest for meaningless statistical correlations.