organochlorines: Immune cell counts and risks of respiratory infections among infants exposed pre- and post-natally to organochlorine compounds: a prospective study

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Immune cell counts and risks of respiratory infections among infants

exposed pre- and post-natally to organochlorine compounds: a prospective

study

http://www.ehjournal.net/content/7/1/62

PDF <http://www.ehjournal.net/content/pdf/1476-069x-7-62.pdf>

Anders Glynn, Ann Thuvander, Marie Aune, Anders Johannisson, Per Ola

Darnerud, Gunnar Ronquist and Sven Cnattingius

Environmental Health 2008, 7:62doi:10.1186/1476-069X-7-62

Background

Early-life chemical exposure may influence immune system development,

subsequently affecting child health. We investigated immunomodulatory

potentials of polychlorinated biphenyls (PCBs) and p,p'-DDE in infants.

Methods

Prenatal exposure to PCBs and p,p'-DDE was estimated from maternal serum

concentrations during pregnancy. Postnatal exposure was calculated from

concentrations of the compounds in mother's milk, total number of

nursing days, and percentage of full nursing each week during the 3

month nursing period. Number and types of infections among infants were

registered by the mothers (N=190). White blood cell counts (N=86) and

lymphocyte subsets (N=52) were analyzed in a subgroup of infants at 3

months of age.

Results

Infants with the highest prenatal exposure to PCB congeners CB-28, CB-52

and CB-101 had an increased risk of respiratory infection during the

study period. In contrast, the infection odds ratios (ORs) were highest

among infants with the lowest prenatal mono-ortho PCB (CB-105, CB-118,

CB-156, CB-167) and di-ortho PCB (CB-138, CB-153, CB-180) exposure, and

postnatal mono- and di-ortho PCB, and p,p'-DDE exposure. Similar results

were found for pre- and postnatal CB-153 exposure, a good marker for

total PCB exposure. Altogether, a negative relationship was indicated

between infections and total organochlorine compound exposure during the

whole pre- and postnatal period. Prenatal exposure to CB-28, CB-52 and

CB-101 was positively associated with numbers of lymphocytes and

monocytes in infants 3 months after delivery. Prenatal exposure to

p,p'-DDE was negatively associated with the percentage of eosinophils.

No significant associations were found between PCB and p,p'-DDE exposure

and numbers/percentages of lymphocyte subsets, after adjustment for

potential confounders.

Conclusions

This hypothesis generating study suggests that background exposure to

PCBs and p,p'-DDE early in life modulate immune system development.

Strong correlations between mono- and di-ortho PCBs, and p,p'-DDE

exposures make it difficult to identify the most important contributor

to the suggested immunomodulation, and to separate effects due to pre-

and postnatal exposure. The suggested PCB and p,p'-DDE modulation of

infection risks may have consequences for the health development during

childhood, since respiratory infections early in life may be risk

factors for asthma and middle ear infections.

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