BACKGROUND: Nationally, average mercury levels among Asians are more than three times higher than other racial/ethnic groups. Because of dietary preferences, such as heavy fish consumption, and potentially use of imported products contaminated with heavy metals, Asians may be disproportionately vulnerable to adverse health effects. Existing education efforts have had limited impact on immigrants and non-English speakers. Research identifying affected communities and characterizing risk factors can help inform intervention efforts. The current study aimed to evaluate the levels of blood metals in a cohort of low-income Chinese adults in San Francisco, and how these levels vary by lifestyle behaviors.
METHODS: Participants included a convenience sample of 96 Chinese adults in the San Francisco Bay Area that completed a questionnaire and gave a blood sample as part of the Asian/Pacific Islander Community Exposures Project (ACE) in 2016. Blood mercury, cadmium, and lead levels were analyzed by inductively coupled plasma mass spectrometry at the California Department of Public Health Environmental Health Laboratory. Geometric means for each metal were calculated and compared to 2013-2014 National Health and Nutrition Examination Survey (NHANES) results. Additionally, we identified factors predicting increased exposure using multivariable linear regression.
RESULTS: ACE participants had higher mercury, cadmium, and lead levels than the adult NHANES population. Participants also had higher mercury levels than adult Non-Hispanic Asian NHANES participants. Preliminary results from a crude analysis of the first batch of lab results (n=56) indicate that mercury, cadmium, and lead levels varied by birth country and most frequent source of buying fish. Years living in the U.S., increased age, and lower income were associated with higher cadmium and lead. Additional predictors for increased individual metals are listed below. Mercury: recent fish consumption, eating fish paste/cake/balls in the past year, frequent consumption of fish caught personally/by family/friends, and former- versus non-smoker status; cadmium: female sex, consumption of shellfish caught personally/by family/friends, and less education; and lead: male sex and current- versus non-smoker status.
CONCLUSIONS: Results support findings from national studies that Chinese communities may be especially vulnerable to heavy metal exposure and potential adverse health outcomes. Exposure assessment findings may reinforce research linking fish consumption and mercury exposure. Other lifestyle and demographic factors may play a role in exposure levels of mercury, cadmium, and lead. Limitations of a convenience sample should be considered. Future research and culturally-appropriate interventions focusing on heavy metal exposure are especially prudent for Chinese and additional Asian sub-populations.