Association of Rice and Rice-Product Consumption With Arsenic Exposure Early in Life

Abstract

Importance: Rice-a typical first food and major ingredient in various infant foods-contains inorganic arsenic (As), but the extent of As exposure from these foods has not been well characterized in early childhood.

Objective: To determine the types and frequency of rice and rice-containing products consumed by infants in the first year of life and the association with As biomarker concentrations.

Design, setting, and participants: Included were infants from singleton births of pregnant women enrolled in the New Hampshire Birth Cohort Study from 2011 to 2014 whose parents were interviewed during their first year of life. Enrolled women from selected clinics were aged 18 to 45 years, living in the same residence since their last menstrual period, in households served by a private water system, and had no plans to move during pregnancy. Data on infants' intake of rice and rice products were collected from interviews with their parents at 4, 8, and 12 months' follow-up and from a 3-day food diary at 12 months from March 2013 to August 2014.

Exposures: Infants' intake of rice and rice products.

Main outcomes and measures: Total urinary As and the sum of As species measured using inductively coupled mass spectrometry and high-performance liquid chromatography with inductively coupled mass spectrometry. Commonly reported infant rice snacks were tested for As.

Results: We obtained dietary data on 759 of 951 infants (79.8% participation rate). Of these, 391 infants (51.7%) were male, and the mean (SD) gestational age was 39.4 (1.7) weeks. An estimated 80% were introduced to rice cereal during their first year. At 12 months, 32.6% of infants (42 of 129) were fed rice snacks. Among infants aged 12 months who did not eat fish or seafood, the geometric mean total urinary As concentrations were higher among those who ate infant rice cereal (9.53 µg/L) or rice snacks (4.97 µg/L) compared with those who did not eat rice or rice products (2.85 µg/L; all P < .01). Infant rice snacks contained between 36 and 568 ng/g of As and 5 to 201 ng/g of inorganic As.

Conclusions and relevance: Our findings indicate that intake of rice cereal and other rice-containing foods, such as rice snacks, contribute to infants' As exposure and suggest that efforts should be made to reduce As exposure during this critical phase of development.

Figure 1. Prevalence of Rice and Rice-Product Consumption and Association With Urinary Arsenic Concentrations Among 129 Infants at 12 Months

^aError bars indicate the back-transformed confidence intervals. ^bP < .001 for pairwise comparisons of infants who consumed rice with infants who consumed no rice or rice products in general linear models that also included specific gravity. ^cP < .05 for pairwise comparisons of infants who consumed rice with infants who consumed no rice or rice products in general linear models that also included specific gravity. ^dP < .01 for pairwise comparisons of infants who consumed rice with infants who consumed no rice or rice products in general linear models that also included specific gravity.

Figure 2. Log₁₀-Transformed Total Urinary Arsenic (TUAs) According to Rice Food Intake Among 129 Infants

P < .001 from a general linear model including specific gravity to account for urinary dilution and the 3 rice food intake categories (F_2,130 = 9.55). Infants who did not consume rice had lower log₁₀-transformed TUAs than infants who consumed either foods mixed with rice (Tukey honestly significant difference test, P = .02) or pure rice (Tukey honestly significant difference test, P < .001). There was no difference between infants who consumed foods mixed with rice or pure rice (Tukey honestly significant difference test, P = .14).

Figure 3. Log₁₀-Transformed Summed Speciated Urinary Arsenic (SUAs) According to Rice Food Intake Among 48 Infants

P < .001 from a general linear model including specific gravity to account for urinary dilution and the 3 rice food intake categories (F_2,45 = 9.02). Infants who did not consume rice had lower log₁₀-transformed SUAs than infants who consumed either foods mixed with rice (Tukey honestly significant difference test, P = .04) or pure rice (Tukey honestly significant difference test, P < .001). There was no difference between infants who consumed foods mixed with rice or pure rice (Tukey honestly significant difference test, P = .20).