The US Food and Drug Administration (FDA) has conducted the Total Diet Study (TDS) since 1961, which designed to monitor the US food supply for chemical contaminants, nutritional elements, and toxic elements. Recently, perchlorate was analyzed in TDS samples. Perchlorate is used as an oxidizing agent in rocket propellant, is found in other items (e.g., explosives, road flares, fireworks, and car airbags), occurs naturally in some fertilizers, and may be generated under certain climatic conditions. It has been detected in surface and groundwater and in food. Perchlorate at high (e.g., pharmacological) doses can interfere with iodide uptake into the thyroid gland, disrupting its function. The National Academy of Sciences (NAS) has identified that ''the fetuses of pregnant women who might have hypothyroidism or iodide deficiency as the most sensitive population.'' This study reports on intake estimates of perchlorate and iodine, a precursor to iodide, using the analytical results from the TDS. Estimated average perchlorate and iodine daily intakes as well as the contribution of specific food groups to total intakes were estimated for 14 age/sex subgroups of the US population. The estimated smallest lower bound to the largest upper bound average perchlorate intakes by the 14 age/sex groups range from 0.08 to 0.39 micrograms per kilogram body weight per day (mg/kg bw/day), compared with the US Environmental Protection Agency (EPA) reference dose (RfD) of 0.7 mg/kg bw/day. Infants and children demonstrated the highest estimated intakes of perchlorate on a body weight basis. The estimated average iodine intakes by the 14 age/sex groups reveal a lower bound (ND ¼ 0) and upper bound (ND ¼ LOD) range of average intakes from 138 to 353 mg/person/day. Estimated iodine intakes by infants 6-11 months exceed their adequate intake (AI), and intakes by children and adult age/sex groups exceed their relevant estimated average requirement (EAR).

Aims This work aimed to assess the performance of hair and fingernail ethyl glucuronide (EtG) measurement for use as a biomarker of alcohol consumption in persons with known drinking history across a range of drinking behaviours. Methods EtG concentrations were assessed from the hair and fingernails of 50 study participants. Alcohol consumption of the previous 90 days was assessed by participant interview using the alcohol timeline follow-back method. EtG concentration was determined using LC–MS-MS using a method which was validated and accredited to ISO/IEC 17025 standards. Results There was significant correlation between alcohol consumption and EtG concentrations found in hair and fingernail samples across the study group (n = 50). From participants testing positive for EtG (male n = 14, female n = 13) no significant difference was found between male and female EtG levels in either hair or fingernails. Across all participants there was no significant difference in hair or fingernail EtG concentration between male (n = 23) and females (n = 27). Conclusions Our results support the use of EtG to indicate alcohol consumption over the previous 90 days, or ~3 months as is the normal practice in hair analysis. The results confirm that fingernails can be a useful alternative matrix where hair samples are not available.

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In Reply In their Letter to the Editor about our study, 1 Dr Omata and colleagues posit that the finding of higher antimicrobial use in nursing home residents in nonmetropolitan areas may have been due to lower participation in antimicrobial stewardship CME by prescribers in rural areas. Our prevalence survey of antimicrobial use in US nursing homes 1 was not designed or powered to be able to provide accurate or meaningful comparisons of state-level data. State-to-state differences in antimicrobial use and stewardship practices likely do exist in nursing homes, as they do in community and hospital prescribing. 2 Undoubtedly, education for physicians and other health care personnel who prescribe antimicrobials is an essential component of an antimicrobial stewardship program. However, the difference observed in antimicrobial use in nonmetropolitan vs metropolitan nursing home residents is likely multifactorial and not solely due to differences in CME requirements.We agree with Omata and colleagues that an in-depth analysis of prescriber characteristics may be important to fully understand patterns of antimicrobial use and to implement interventions that address selected prescribing behaviors in nursing homes. While the process of antimicrobial prescribing in nursing homes is complex and different from that in hospital and clinic settings, 3 the factors that influence antimicrobial use in nursing homes are not well described. 1 A retrospective analysis of data obtained from linked population-based administrative databases for long-term care residents in 630 longterm care facilities in Ontario, Canada, found that prescriber preferences were more important determinants of antibiotic treatment duration than patient characteristics. 4 While an important area of inquiry, it was not an aim of our prevalence survey to describe antimicrobial prescriber characteristics; therefore, we do not have this information available to share. Data collection on prescriber characteristics is not well suited to the prevalence survey approach, especially in nursing homes, where the process of prescribing is complex and many residents are admitted for antimicrobial therapy from other health care settings. 1 Alternative study designs, including those based on administrative data 4 or electronic health and medication administration records, may be better suited to facilitate the collection of data on prescriber characteristics.