Daniel et al. Series-4 fluorometer (VICAM) set at 360 nm excitation and 450 nm emissions. This method has an aflatoxin recovery of ≥ 85% and a detection limit of 1 ppb. Statistical analysis of the data. We cal- culated descriptive statistics, including the number and percentage of maize samples > 20 ppb, the Kenyan regulatory limit for aflatoxins in grains for human consumption (FDA 2000), and geometric mean (GM) aflatoxin levels. When estimating GMs, the values that were less than the limit of detec- tion (LOD) were substituted with the LOD divided by the square root of two. The p-value used was 0.05. We used mixed linear models to investigate the association between afla- toxin concentration in maize samples and selected items from the questionnaire, includ- ing source of the maize, geographic location of the household (e.g., division and village), and questions measuring aflatoxin aware- ness. In these analyses, aflatoxin concentra- tion levels were log-transformed to normalize. Because the village selection methods varied slightly between years, we conducted analyses separately by year. A random effect of village within division group was included in each model. In addition, we combined the data from 2005, 2006, and 2007 to calculate sum- mary estimates of aflatoxin contamination, source, and awareness data adjusted for year. We calculated least square means for the fixed effects specified in the models (e.g., year and source). We analyzed aflatoxin concentration and questionnaire data using SAS software (version 9.2; SAS Institute, Cary, NC, USA). Results Description of study sample. In the 3 years combined, we surveyed a total of 99 villages: 46 in the Makueni district and 53 in the Kitui district. Within those villages, we sur- veyed 705 households. Most [676 (96%)] of these households were randomly selected, and the remaining 29 (4%) were systemati- cally selected households with an aflatoxicosis case-patient (cases who had been hospitalized) who was identified by hospital-based clinical disease surveillance in 2005 (Table 1). Eleven of the 705 households had maize from two different sources; therefore, we collected a total of 716 maize samples. We collected most (42%) of the 716 samples in 2005, followed by 35% in 2007, and 23% in 2006. Table 1. Description of study sample by year. Households Maize samples n (%) 289 (41)a 160 (23) 256 (36) 705 (100) n (%) 298 (42) 165 (23) 253 (35) 716 (100) aIn 2005, the total number of households includes 260 households randomly selected and 29 households of case–patients identified by hospital reporting. Year 2005 2006 2007 Total 1796 Villages n (%) 36 (36) 38 (38) 25 (25) 99 (100) Maize production. In 2005, most par- ticipants (96%) reported that their maize crop production was less than in previous years, and only 83 (28%) of the 298 maize samples collected were homegrown (grown on the household farm), whereas 215 (72%) were either purchased or obtained from the Kenyan government. In contrast, 97 (59%) of the maize samples collected in 2006 were homegrown. On average, households reported harvesting 328 kg (approximately four 90-kg bags) of maize in 2006. Maize production increased substantially in 2007 compared with the previous 2 years. All of the 256 samples collected in 2007 were homegrown, and none of the households reported purchasing maize or requesting relief maize. On average, house- holds reported harvesting 1,169 kg (13 bags) of maize, or triple the harvest of 2006. Aflatoxin contamination. For all 3 years combined (2005, 2006, and 2007), maize aflatoxin levels ranged from nondetectable to 48,000 ppb. The GM aflatoxin level for all 3 years combined was 9.10 ppb, and more than a third [248 (35%)] of the 716 maize samples had aflatoxin levels above the 20-ppb regula- tory limit (Table 2). However, aflatoxin levels varied considerably by year, with GM levels decreasing dramatically in 2007 (GM = 1.95) compared with 2005 (GM = 12.92) and 2006 (GM = 26.03; p-value < 0.0001) (Table 2). We collected the maize sample with the highest aflatoxin level (48,000 ppb—2,400 times the regulatory limit for human consump- tion) in 2005, and the sample with the sec- ond highest level (24,400 ppb) in 2006. In the non-outbreak year (2007), contamination was much lower than in the previous 2 years; the two samples with the highest contamination had aflatoxin levels of 2,500 ppb and 470 ppb. In 2005 and 2006, 41% and 51% of sam- ples, respectively, had aflatoxin levels above the 20-ppb regulatory limit compared with 16% of samples in 2007 (Table 2). In addition, 21 samples (7%), 14 samples (8%), and 1 sam- ple (0.4%) had aflatoxin levels > 1,000 ppb in 2005, 2006, and 2007, respectively (Table 2). Source of maize and aflatoxin contamina- tion. We assessed and compared the extent of aflatoxin contamination in the three sources of maize in the region (homegrown, pur- chased, and relief) in 2005 and 2006 when all three sources of maize were collected from households and tested. In 2007, production was high, and all households had only home- grown maize. Most of the homegrown maize samples collected in 2005 and 2006 had afla- toxin levels above the 20-ppb regulatory limit (64% and 60%, respectively) compared with 41% and 40% of purchased maize samples (Table 3). Of the relief maize tested, three of 53 (6%) relief samples in 2005 and one of three (33%) in 2006 exceeded the 20-ppb limit. We found the highest levels of aflatoxin contamination in 2005 and 2006 (48,000 ppb and 24,400 ppb, respectively) in home- grown maize samples. Relief maize had con- siderably lower aflatoxin levels (see Table 3). In 2005, the aflatoxin level of homegrown maize (GM = 62.61) was significantly higher than the level of purchased maize (GM = 10.05) or of relief maize (GM = 1.99) (p-value < 0.0001). We also found similar, statistically significant differences in levels among the different sources in 2006 (p-value < 0.0001) (Table 4). When comparing aflatoxin levels in homegrown maize between years, the GM homegrown maize aflatoxin levels were sig- nificantly higher in 2005 (GM = 17.96) and 2006 (GM = 3.64) compared with 2007 (GM = 0.73) (p-value < 0.0001). We found no significant difference in homegrown maize aflatoxin levels in 2005 compared with 2006. Aflatoxin contamination and jaundice. We asked questions about the health of family members residing in the household, specifically, if any household members had symptoms of jaundice. Of the 696 randomly selected households in all 3 years combined (not including the aflatoxicosis case house- holds), 13 (2%) reported that one or more family members residing in the household had symptoms of jaundice at the time the survey was conducted. The GM aflatoxin levels in maize being consumed by households report- ing jaundice ranged from 4.02 to 18.57 ppb. The maximum aflatoxin levels found among households with jaundice was 820 ppb. No jaundice was reported among households con- suming maize with aflatoxin levels > 1,000 ppb, including those consuming the highest concentrations (48,000 ppb, 24,000 ppb). Aflatoxin awareness. When assessing afla- toxin awareness, we limited our analysis to the 436 respondents who had homegrown maize Table 2. Summary of the extent of aflatoxin contamination among all households, 2005–2007. 2005 2006 2007 All years combined No. of samples tested 298 165 253 716 Overall GM (range)a 12.92 (0.11–48,000) 26.03 (0.30–24,400) 1.95 (< LOD–2,500) 9.10 (< LOD–48,000) Households with aflatoxin < 20 ppb (%) 59 48 84 65 20–200 ppb (%) 23 28 13 21 201–1,000 ppb (%) 11 15 3 9 > 1,000 ppb (%) 7 8 0.4 5 aAll estimates are adjusted for division and village using mixed linear models. ovlume 119 | number 12 | December 2011 • Environmental Health Perspectives