Erythrocyte omega-3, omega-6 and trans fatty acids in relation to risk of preeclampsia among women delivering at Harare Maternity Hospital, Zimbabwe

Abstract

We sought to examine the association between maternal erythrocyte omega-3, omega-6 and trans fatty acids and risk of preeclampsia. We conducted a case-control study of 170 women with proteinuric, pregnancy-induced hypertension and 185 normotensive pregnant women who delivered at Harare Maternity Hospital, Harare, Zimbabwe. We measured erythrocyte omega-3, omega-6 and trans fatty acid as the percentage of total fatty acids using gas chromatography. After multivariate adjustment for confounding factors, women in the highest quartile group for total omega-3 fatty acids compared with women in the lowest quartile experienced a 14% reduction in risk of preeclampsia (odds ratio 0.86, 95% confidence interval 0.45 to 1.63). For total omega-6 fatty acids the odds ratio was 0.46 (95% confidence interval 0.23 to 0.92), although there was suggestion of a slight increase in risk of preeclampsia associated with high levels of arachidonic acid. Among women in the highest quartile for arachidonic acid the odds ratio was 1.29 (95% confidence interval 0.66 to 2.54). A strong statistically significant positive association of diunsaturated fatty acids with a trans double bond with risk of preeclampsia was observed. Women in the upper quartile of 9-cis 12-trans octadecanoic acid (C(18:2n6ct)) compared with those in the lowest quartile experienced a 3-fold higher risk of preeclampsia (odds ratio = 3.02, 95% confidence interval 1.41 to 6.45). Among women in the highest quartile for 9-trans 12-cis octadecanoic acid (C(18:2n6tc)) the odds ratio was 3.32 (95% confidence interval 1.55 to 7.13). Monounsaturated trans fatty acids were also positively associated with the risk of preeclampsia, although of much reduced magnitude. We observed a strong positive association of trans fatty acids, particularly diunsaturated trans fatty acids, with the risk of preeclampsia. We found little support for the hypothesized inverse association between omega-3 fatty acids and preeclampsia risk in this population. Polyunsaturated fatty acids, particularly omega-3 fatty acids, were comparatively lower in Zimbabwean than among US pregnant women. Given the limited inter-person variation in omega-3 fatty acids among Zimbabwean women, our sample size may be too small to adequately assess the relation in this population