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Handbook of Solvents - George Wypych - ChemTech - Ventech!

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1344 Kristen I. McMartin, Gideon Koren<br />

Of concern is the potential selection bias due to differing patterns <strong>of</strong> use <strong>of</strong> medical services.<br />

The primary determinant for seeking medical care is probably gestational age so that earlier<br />

abortions are less likely to be medically recorded than later abortions. 29 The advantage <strong>of</strong><br />

data on medically diagnosed spontaneous abortions, compared to interview data is that the<br />

former are independent <strong>of</strong> an individuals own definition, recognition and reporting.<br />

In total, 5 papers describing results from organic solvent exposure were identified (Table<br />

20.3.4). The summary odds ratio obtained was 1.25 (95% CI: 0.99 - 1.58). The test for<br />

homogeneity yielded a chi square=4.88 (df=4, p=0.300). When studies were analyzed separately<br />

according to study type, the chi-square value for homogeneity <strong>of</strong> effect for cohort<br />

studies was 4.20 (df=3, p=0.241). Meta-analysis <strong>of</strong> both cohort and case-control studies<br />

produced similar results, i.e., they do not demonstrate a statistically significant relationship<br />

between organic solvent exposure in pregnancy and spontaneous abortion. The summary<br />

odds ratio for cohort studies was 1.39 (95% CI: 0.95 - 2.04) and 1.17 (95% CI: 0.87 - 1.58)<br />

for case control studies. Their combinability seems justified on the basis <strong>of</strong> the lack <strong>of</strong> finding<br />

heterogeneity among the results.<br />

Table 20.3.4. Results <strong>of</strong> studies comparing outcomes <strong>of</strong> fetuses exposed or not<br />

exposed to organic solvents. [Adapted, by permission, from K.I. McMartin, M. Chu, E.<br />

Kopecky, T.R. Einarson and G. Koren, Am. J. Ind. Med., 34, 288 (1998) Copyright 1998<br />

John Wiley & Sons, Inc. Reprinted by permission <strong>of</strong> Wiley-Liss, Inc. a division <strong>of</strong> John<br />

Wiley & Sons, Inc.]<br />

Reference Exposure<br />

Windham et al. 21<br />

Lipscomb et al. 22<br />

Schenker et al. 23<br />

Pinney 24<br />

Eskenazi et al. 25<br />

TOTAL<br />

any solvent product yes<br />

no<br />

total<br />

organic solvent yes<br />

no<br />

total<br />

organic solvents yes<br />

no<br />

total<br />

organic solvents yes<br />

no<br />

total<br />

organic solvents yes<br />

no<br />

total<br />

yes<br />

no<br />

total<br />

yes<br />

Spontaneous Abortion<br />

no total<br />

89<br />

272<br />

361<br />

10<br />

87<br />

97<br />

12<br />

16<br />

28<br />

35<br />

25<br />

60<br />

4<br />

7<br />

11<br />

150<br />

407<br />

557<br />

160<br />

575<br />

735<br />

39<br />

854<br />

893<br />

8<br />

21<br />

29<br />

228<br />

166<br />

394<br />

97<br />

194<br />

291<br />

532<br />

1810<br />

2342<br />

249<br />

847<br />

1096<br />

49<br />

941<br />

990<br />

20<br />

37<br />

57<br />

263<br />

191<br />

454<br />

101<br />

201<br />

302<br />

682<br />

2217<br />

2899<br />

The overall ORs <strong>of</strong> 1.25 indicates that maternal inhalational occupational exposure to<br />

organic solvents is associated with a tendency towards a small increased risk for spontaneous<br />

abortion. The addition <strong>of</strong> one study <strong>of</strong> similar effect size would have rendered this trend<br />

statistically significant.

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