Objectives: To examine the association between aflatoxin (AF) exposure during pregnancy and rate of gestational weight gain (GWG) in a sample of pregnant women of mixed HIV status in Gulu, northern Uganda. Methods: 403 pregnant women were included (133 HIV-infected on antiretroviral therapy (ART), 270 HIV-uninfected). Women’s weight, height and socio-demographic characteristics were collected at baseline (~19 weeks’ gestation); weight was assessed at each follow-up visit. Serum was collected at baseline and tested for aflatoxin B1-lysine adduct (AFB-lys) levels using high-performance liquid chromatography (HPLC). Linear mixed-effects models were used to examine the association between AFB-lys levels and rate of GWG. Results: AFB-lys levels (detected in 98.3% of samples) were higher among HIV-infected pregnant women than HIV-uninfected pregnant women [median (interquartile range): 4.8 (2.0, 15.0) vs. 3.5 (1.6, 6.1) pg/mg of albumin, P < 0.0001]. Adjusting for HIV status, a one-log increase in aflatoxin levels was associated with a 16.2 g per week lower rate of GWG (P = 0.028). The association between AFB-lys and the rate of GWG was stronger and significant only among HIV-infected women on ART [−25.7 g per week per log (AFB-lys), P = 0.009 for HIV-infected women vs. −7.5 g per week per log (AFB-lys), P = 0.422 for HIV-uninfected women]. Conclusions: Pregnant women with higher levels of AF exposure had lower rates of GWG. The association was stronger for HIV-infected women on ART, suggesting increased risk.
Data for this study were collected from 2012 to 2013 as part of the Prenatal Nutrition and Psychosocial Health Outcomes (PreNAPs) study. PreNAPs was an observational, longitudinal cohort study designed to explore relationships among food access, nutritional and psychosocial exposures, and several physical and mental health outcomes in a sample of 403 HIV‐infected (n = 133) and HIV‐uninfected (n = 270) pregnant women in Gulu, northern Uganda. The study was approved by Cornell University’s Institutional Review Board (IRB), Gulu University’s Institutional Review Committee and the Uganda National Council for Science and Technology (UNCST). Written informed consent was obtained from all participants prior to enrolment. The parent study was registered at ClinicalTrials.gov as {"type":"clinical-trial","attrs":{"text":"NCT02922829","term_id":"NCT02922829"}}NCT02922829. PreNAPs methodology (i.e. recruitment process, inclusion and exclusion criteria, response rates, and reasons for refusal to participate) has been previously reported [39, 40]. Briefly, pregnant women were recruited from the antenatal clinic (ANC) of Gulu Regional Referral Hospital (GRRH; i.e. Gulu Hospital), located in Gulu, northern Uganda. HIV‐infected and HIV‐uninfected pregnant women who presented at the ANC between 10‐ and 26‐week gestation (assessed according to women’s recall of the first date of their last menstrual period), resided within 30 km of GRRH and had a known HIV status were eligible to participate in PreNAPs. Women whose HIV status was unknown were excluded from participation. Of the 415 pregnant women asked to participate in PreNAPs, 405 accepted, while 10 refused citing lack of time. Of the 405 participating women, complete data on all the variables of interest for this analysis were available for 403 women. In PreNAPs, HIV‐infected women were oversampled in order to achieve a minimum ratio of 1 HIV‐infected: 2 HIV‐uninfected participants. The sample size for PreNAPs was designed to provide 80% power to detect a 50‐g difference in weight gain between HIV‐infected and HIV‐uninfected women at a 5% level of significance and accounting for a 10% loss to follow‐up. Women in PreNAPs were followed monthly throughout their pregnancy (mean ± SD prenatal visits per woman: 5.0 ± 1.1). Women were tested for HIV at the ANC of GRRH per Government of Uganda (GoU) guidelines [41]. All HIV‐infected pregnant women were participating in a GoU ART programme to prevent mother‐to‐child transmission of HIV. Antiretroviral drugs were provided to all HIV‐infected pregnant women following the GoU [41] and WHO [42] guidelines. At enrolment, socio‐demographic data were collected for all women including age, parity (nulliparous vs. other), marital status (separated, divorced or widowed vs. other) and education level (primary level or lower vs. higher than primary level). Maternal height and weight were measured at enrolment (Seca 206 for height; Seca 874 for weight; Seca North America, Chino, CA, USA). Weight was re‐assessed at all follow‐up visits. Gestational age of the index pregnancy was determined using women’s recall of the first date of their last menstrual period. Rate of GWG was calculated by dividing the difference of maternal weight between the last and first monthly visit by the corresponding difference of gestational weeks. Dietary diversity was assessed using the Minimum Dietary Diversity for Women (MDD‐W) indicator [43]. Finally, women were asked about possession of 20 household assets contained in the socio‐economic module of the 2009–2010 Uganda National Panel Survey Questionnaire [44]. An asset index was generated using principal components analysis methodology [45]. Serum samples were temporarily stored at −20 °C in Gulu, northern Uganda, and then transferred to Kampala, Uganda, where they were stored at −80 °C. Samples were then shipped to the laboratory at the University of Georgia, Athens, GA, USA, for analysis. AF exposure was assessed via serum levels of the AFB‐lys adduct using previously described high‐performance liquid chromatography (HPLC)‐fluorescence methods [46, 47]. This included measurement of albumin and total protein concentrations for each sample, digestion with protease to release amino acids, concentration and purification of the AFB‐lysine adduct, and finally separation and quantification by HPLC. Household geographic coordinates were obtained for 150 women in the sample. Women’s households were then mapped using geographic information system (GIS) software (ArcGIS, Esri, Redlands, CA, USA) according to HIV status (infected vs. uninfected) as well as serum AFB‐lys level. AF exposure data were grouped into five ranges of values determined by the natural breaks (jenks) classification method [48]. The Anselin Local Moran's I statistic tool [49] was used to determine whether there were statistically significant hot spots, cold spots and/or cluster outliers of HIV infection or AF levels using an inverse distance relationship. The main objective of this study was to determine the effect of AF exposure on the rate of GWG in a sample of pregnant women of mixed HIV status. Due to their skewed distribution, AFB‐lys levels were log‐transformed prior to analyses. Baseline characteristics for mothers were calculated and are presented as mean ± SD or n (%). Student’s t‐tests were used to compare baseline characters between HIV‐infected and HIV‐uninfected women. Associations between AFB‐lys levels and baseline characteristics were assessed using either Spearman’s correlation coefficients in the case of continuous variables or Mann–Whitney tests in the case of categorical variables. Linear mixed‐effects models were used to determine the unadjusted and HIV status‐adjusted differences in the rate of GWG per unit increase in baseline log AFB‐lys levels. Thereafter, separate models were fit for HIV‐infected women and HIV‐uninfected women to examine whether the effect of AFs on the rate of GWG differed in the two study groups. Data were analysed using Stata 15 software (StataCorp, College Station, TX, USA). For all analyses, P < 0.05 was considered statistically significant.