Concerns about lead exposure

AORN Journal,  Sept, 2007  by Jerry Dyer,  Patricia Stein

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My wife, a retired OR nurse, decided to give me a test on her understanding of the article "Total anomalous pulmonary venous connection" (TAPVC) (Vol 85, March 2007). Her thinking was that if she could correctly describe the normal and abnormal functionings of the human heart to me--a layman--then she would have mastered the material herself. Since I have no background in medicine, I must compliment her on both her understanding of the article and on her ability to teach me enough so that I now have at least a rudimentary understanding.

On page 511, the article mentions "an association between TAPVC and self-reported maternal lead exposure during the first trimester and an association with paternal exposure to lead six months before conception occurred." This raised a question in both our minds: where, how, and why were the study participants exposed to lead? We think it is important to clarify the ways in which both the mothers and fathers of these children were involved with lead. Did they ingest lead, inhale lead, have tactile contact with lead?

Both my wife and I grew up in the Baltimore area (ie, the site of the study), so we were rather personally concerned about this lead exposure. It seems the most common source of lead for the general population--especially in an old city like Baltimore--is through lead-based paint, so it would be interesting and important to report on the mechanisms of how lead can enter the human system.

JERRY DYER

YORK, PA

AUTHOR'S RESPONSE, Thank you for your close reading of the article on TAPVC, which is a congenital anomaly of the heart that occurs very shortly after conception. The two articles that I used for the information about the effect of lead exposure on the chances of a baby having a congenital heart defect come from the Baltimore-Washington Infant Study. (1,2) This was a population-based, exploratory, case-control study of cardiovascular malformations from 1981 to 1987. Within this group, there were 41 cases of TAPVC (ie, 1.5% of the live births). The regional prevalence was 6.8 per 100,000.

Compared to a control group, more TAPVC patients had low birthweight, short gestational age (ie, less than 38 weeks) and intrauterine growth retardation. One article states,

   Bivariate analysis of [TAPVC] and exposure in life-style, hobbies,
   and work showed possible associations for exposure to lead ([odds
   ratio] OR 2.9; 99% confidence interval [CI]: 1.2, 7.2)
   painting/paint stripping (OR 3.3; 99% Ch 1.3, 8.4), lead soldering
   (OR 13.3; 99% Ch 1.8, 99.2) and pesticides (OR 2.7; 99% Ch 1.2,
   6.4). (1(p415)

In 2003, information presented at the 43rd Tetralogy Society Conference in Philadelphia, Pennsylvania, followed up on a reported association between self-reported maternal lead exposure and TAPVC in offspring. Parental lead exposure was based on an industrial hygiene assessment, an a priori job exposure matrix, and self-reported exposures. The parent was classified as lead-exposed if any of the assessment categories fit.

The authors state that

   Approximately 17% of case mothers and 11% of control mothers were
   classified as exposed to lead during the three months prior to
   conception through the first trimester.... Among fathers, 61% of
   case fathers and 46% of control fathers were classified as exposed
   to lead during the six months prior to conception (paternal
   critical period).... During the paternal critical period, when only
   the father was exposed compared to neither parent exposed, the OR
   for any lead exposure and [TAPVC] was 1.65 (95% CL 0.84-3.25).
   (2(p185))

The above information suggests the answer to the question, "Did they ingest lead, inhale, lead, have tactile contact with lead?" I would say all three occurred.

REFERENCES

(1.) Correa-Villasenor A, Ferencz C, Boughman JA, Neill CA; The Baltimore-Washington Infant Study Group. Total anomalous pulmonary venous return: familial and environmental factors. Tetralogy. 1991; 44(4): 415-428.

(2.) Jackson LW, Correa-Villasenor A, Lees PS, et al. Parental lead exposure and total anomalous pulmonary venous return. Birth Defects Res A Clin Mol Teratol. 2004;70(4):185-193.

PATRICIA STEIN

RN, BSN, MAOL, CNOR

NURSE EDUCATION SPECIALIST FOR PERIOPERATIVE SERVICES

PALOMAR POMERADO HEALTH

ESCONDIDO, CA

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