Hightower et al. includes all participants who self-identiﬁed as Asian, Paciﬁc Islander, Native American, mul- tiracial, or a race/ethnicity other than black, non-Hispanic white, Mexican American, or Hispanic) with those in all other racial/ethnic groups (CDC 2005; National Center for Health Statistics 2005). Study sample. All women 16–49 years of age who were selected for both the interview and examination portions of NHANES and underwent whole-blood mercury testing were eligible for inclusion (n = 3,873). Among these, 236 participants had missing blood mercury results and were thus excluded from the analytic sample (n = 3,637). Among the women included in the analysis, 1,377 self- identified as non-Hispanic white, 1,106 as Mexican American, 794 as non-Hispanic black, and 220 as other Hispanic, and 140 were categorized as “other.” Statistical analysis. We obtained popula- tion prevalence estimates for blood mercury levels ≥ 5.8 µg/L and ≥ 3.5 µg/L, respectively, using appropriate sample weights (Stata statis- tical software for complex survey design; StataCorp., College Station, TX) (CDC 2005; National Center for Health Statistics 2005). We compared the estimated prevalence of ele- vated blood mercury levels among participants in the “other” racial/ethnic group with those among Mexican Americans, non-Hispanic whites, and non-Hispanic blacks. To determine whether observed differences in whole-blood mercury levels were most likely to reﬂect differences in dietary ﬁsh consump- tion rather than exposure to elemental or inor- ganic mercury, we examined self-reported ﬁsh consumption (number of fish and shellfish meals in the preceding 30 days) among female NHANES participants 16–49 years of age (n = 3,481) by racial/ethnic group. We also exam- ined mean urine mercury-to-creatinine ratios (micrograms per gram) across racial/ethnic groups (n = 3,551). These analyses were also conducted using sample weights. Results An estimated 16.59 ± 4.0% [mean ± SE; 95% conﬁdence interval (CI), 8.41–24.77] of adult female participants who self-identified as Asian, Pacific Islander, Native American, or multiracial (n = 140) had blood mercury levels ≥ 5.8 µg/L, and an estimated 27.26 ± 4.22% (95% CI, 18.63–35.90) had levels ≥ 3.5 µg/L. In accordance with the NHANES analytical guidelines, these prevalence estimates are sta- tistically reliable, because the relative SEs did not exceed 30% of the point estimates. The prevalence of elevated blood mercury levels in the “other” group is signiﬁcantly higher than in all other racial/ethnic groups (Table 1). Among the remaining participants (n = 3,497), an estimated 5.08 ± 0.90% (95% CI, 3.25–6.92) had blood levels ≥ 5.8 µg/L, and an estimated 10.86 ± 1.45% (95% CI, 7.90–13.83) had mercury levels ≥ 3.5 µg/L. The mean number of fish and shellfish meals for the “other” racial/ethnic group was higher than for the remaining groups, although the 95% CIs overlapped with all except Mexican Americans. Fish and shellfish con- sumption among Mexican Americans is lower than among the “other” population. There were no statistically significant differences between groups in urine mercury:creatinine ratios (Table 2). Discussion In the United States, 4.1 million people iden- tiﬁed themselves as Alaskan Native or Native American alone or in combination with one or more races in Census 2000; 12.5 million people identiﬁed as Asian or Paciﬁc Islander, with 51% residing in the West, 19% in the South, 12% in the Midwest, and 19% in the Northeast. Asians, Pacific Islanders, Alaskan Natives, and Native Americans accounted for approximately 6.0% of live births in 2001, or approximately 242,151 babies born (U.S. Census Bureau 2002a, 2002b; Ventura et al. 2003). aParticipants who self-identified as Asian, Pacific Islander, Native American, multiracial, or a race/ethnicity other than black, non-Hispanic white, Mexican American, or Hispanic. aParticipants who self-identiﬁed as Asian, Paciﬁc Islander, Native American, multiracial, or as a race/ethnicity other than black, non-Hispanic white, Mexican American, or Hispanic. 174 VOLUME 114 | NUMBER 2 | February 2006 • Environmental Health Perspectives The prevalence of elevated blood mercury, whether this was deﬁned as ≥ 5.8 µg/L or ≥ 3.5 µg/L, was signiﬁcantly higher among members of the “other” racial/ethnic group than among any other racial/ethnic group and primarily reﬂected differences in organic mercury expo- sure, most likely due to ﬁsh consumption. Although reports based on the most recent NHANES data from 2001–2002 have not reported mercury levels for this group (CDC 2004), NHANES data for the years 1999–2000 showed a non-statistically signiﬁ- cant trend toward higher mercury levels in the “other” ethnic group (Mahaffey et al. 2004). Estimates presented here based on four years of NHANES data, 1999–2002, demonstrate that levels of mercury in this group are statistically signiﬁcantly higher than for all other groups considered. Our ﬁndings are consistent with those of smaller studies that showed a correlation of methylmercury through fish consumption within the racial/ethnic groups that comprise the “other” population of NHANES partici- pants. The groups identified in these studies were Native peoples of the United States and Canada (Beuter and Edwards 2004; Bjerregaard and Hansen 2000; Clarkson 1976; Girard et al. 1996; Harnly et al. 1997; McKeown-Eyssen et al. 1983; Mergler et al. 1998; Muckle et al. 2001; Weihe et al. 2002) and residents of Hong Kong and China (Choy et al. 2002; Dickman and Leung 1998; Leung et al. 2001), Japan (Fukuda et al. 1999), and American Samoa (Marsh et al. 1974). In fact, a recent random-digit-dial fish consumption survey (with subsequent hair mercury levels in women 18–45 years of age from 12 states in the continental United States) found that Asians had methylmercury exposures greater than the reference dose 83% of the time, compared with 12% for the total survey population (Knobeloch et al. 2005). Although NHANES was not designed to identify small subgroups at risk, it is Table 2. Fish/shellﬁsh meals and urine Hg:creatinine ratios among women 16–49 years of age participat- ing in NHANES 1999–2002 [mean ± SE (95% CI)]. No. of ﬁsh/shellﬁsh meals in the preceding 30 days Urine Hg:creatinine ratio (µg/g) Race/ethnicity Mexican American Non-Hispanic white Non-Hispanic black Other Hispanic Othera 2.86 ± 0.15 (2.55–3.17) 4.63 ± 0.25 (4.13–5.14) 4.90 ± 0.27 (4.35–5.45) 3.82 ± 0.53 (2.74–4.90) 8.02 ± 1.95 (4.03–12.02) 1.31 ± 0.12 (1.07–1.55) 1.07 ± 0.06 (0.95–1.19) 1.10 ± 0.12 (0.84–1.34) 1.08 ± 0.11 (0.86–1.31) 1.17 ± 0.14 (0.88–1.45) Table 1. Prevalence of elevated blood mercury levels among women 16–49 years of age participating in NHANES 1999–2002 [mean ± SE (95% CI)]. Race/ethnicity Mexican American Non-Hispanic white Non-Hispanic black Other Hispanic Othera race/ethnicity All races/ethnicities except “other” All participants No. 1,106 1,377 794 220 140 3,497 3,637 ≥ 3.5 µg/L (%) 5.71 ± 0.98 (3.70–7.72) 11.29 ± 1.91 (7.40–15.19) 12.47 ± 2.15 (8.08–16.90) 10.38 ± 3.63 (2.95–17.81) 27.26 ± 4.22 (18.63–35.90) 10.86 ± 1.45 (7.90–13.83) 11.69 ± 1.42 (8.79–14.60) ≥ 5.8 µg/L (%) 1.70 ± 0.41 (0.87–2.53) 5.77 ± 1.24 (3.24–8.30) 4.82 ± 1.49 (1.78–7.86) 3.65 ± 1.87 (0.00–7.48) 16.59 ± 4.0 (8.41–24.77) 5.08 ± 0.90 (3.25–6.92) 5.66 ± 0.94 (3.75–7.58)