Will biomonitoring change how we regulate toxic chemicals?

Biomonitoring is the assessment of human exposure to environmental chemicals by measuring the chemicals or their metabolites in human specimens such as blood, urine, saliva, or tissue. It has become a powerful public health tool. This article discusses the practical application of biomonitoring to address a public health problem in a state, to explain how biomonitoring differs from predicting exposure through environmental monitoring, to describe the influence biomonitoring has had on promulgating regulations aimed at protecting public health, and to discuss the position biomonitoring holds in the legal landscape as well as its promise in forging laws that will regulate toxic chemicals more effectively.

Preparedness on the frontline: what's law got to do with it?

The article provides an overview of current work toward identifying core competencies for public health emergency and bio-terrorism response, including law-related competencies. It demonstrates how competency sets are interrelated and how they provide a framework for developing preparedness training for public health leaders, public health and health care professionals, law enforcement, public health attorneys, and others. The health and safety of America's communities hinge on the nation's public health workforce--the estimated 448,254 public health professionals and 3 million related workforce professionals who form the expanded public health system that protects us during times of national crisis and in our daily lives. The response capacity of our health agencies and communities and their ability to respond effectively will be unpredictable without adequate training. Education in the core competencies in emergency preparedness and bio-terrorism response is essential. Preparedness at the front-line means that public health leaders and administrators must be able to communicate information, roles, capacities, and legal authorities to all emergency response partners during planning, drills, and actual emergencies. Each public health worker must be able to describe his or her communication role in emergency response within the agency, with the media, and with the general public. Law enforcement and state government representatives must understand the legal powers of their agencies and of public health agencies for coordinated response, mitigation, and recovery efforts in a public health emergency event.

Comparative validation of the Block, Willett, and National Cancer Institute food frequency questionnaires : the Eating at America's Table Study.

Researchers at the National Cancer Institute developed a new cognitively based food frequency questionnaire (FFQ), the Diet History Questionnaire (DHQ). The Eating at America's Table Study sought to validate and compare the DHQ with the Block and Willett FFQs. Of 1,640 men and women recruited to participate from a nationally representative sample in 1997, 1,301 completed four telephone 24-hour recalls, one in each season. Participants were randomized to receive either a DHQ and Block FFQ or a DHQ and Willett FFQ. With a standard measurement error model, correlations for energy between estimated truth and the DHQ, Block FFQ, and Willett FFQ, respectively, were 0.48, 0.45, and 0.18 for women and 0.49, 0.45, and 0.21 for men. For 26 nutrients, correlations and attenuation coefficients were somewhat higher for the DHQ versus the Block FFQ, and both were better than the Willett FFQ in models unadjusted for energy. Energy adjustment increased correlations and attenuation coefficients for the Willett FFQ dramatically and for the DHQ and Block FFQ instruments modestly. The DHQ performed best overall. These data show that the DHQ and the Block FFQ are better at estimating absolute intakes than is the Willett FFQ but that, after energy adjustment, all three are more comparable for purposes of assessing diet-disease risk.

Design and serendipity in establishing a large cohort with wide dietary intake distributions : the National Institutes of Health-American Association of Retired Persons Diet and Health Study.

In 1995-1996, the authors mailed a food frequency questionnaire to 3.5 million American Association of Retired Persons members who were aged 50-69 years and who resided in one of six states or two metropolitan areas with high-quality cancer registries. In establishing a cohort of 567,169 persons (340,148 men and 227,021 women), the authors were fortunate in that a less-than-anticipated baseline response rate (threatening inadequate numbers of respondents in the intake extremes) was offset by both a shifting and a widening of the intake distributions among those who provided satisfactory data. Reported median intakes for the first and fifth intake quintiles, respectively, were 20.4 and 40.1 (men) and 20.1 and 40.0 (women) percent calories from fat, 10.3 and 32.0 (men) and 8.7 and 28.7 (women) g per day of dietary fiber, 3.1 and 11.6 (men) and 2.8 and 11.3 (women) servings per day of fruits and vegetables, and 20.7 and 156.8 (men) and 10.5 and 97.0 (women) g per day of red meat. After 5 years of follow-up, the cohort is expected to yield nearly 4,000 breast cancers, more than 10,000 prostate cancers, more than 4,000 colorectal cancers, and more than 900 pancreatic cancers. The large size and wide intake range of the cohort will provide ample power for examining a number of important diet and cancer hypotheses.

Is shorter always better? Relative importance of questionnaire length and cognitive ease on response rates and data quality for two dietary questionnaires.

In this study, the authors sought to determine the effects of length and clarity on response rates and data quality for two food frequency questionnaires (FFQs): the newly developed 36-page Diet History Questionnaire (DHQ), designed to be cognitively easier for respondents, and a 16-page FFQ developed earlier for the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial. The PLCO Trial is a 23-year randomized controlled clinical trial begun in 1992. The sample for this substudy, which was conducted from January to April of 1998, consisted of 900 control and 450 screened PLCO participants aged 55-74 years. Controls received either the DHQ or the PLCO FFQ by mail. Screenees, who had previously completed the PLCO FFQ at baseline, were administered the DHQ. Among controls, the response rate for both FFQs was 82%. Average amounts of time needed by controls to complete the DHQ and the PLCO FFQ were 68 minutes and 39 minutes, respectively. Percentages of missing or uninterpretable responses were similar between instruments for questions on frequency of intake but were approximately 3 and 9 percentage points lower (p < or = 0.001) in the DHQ for questions on portion size and use of vitamin/mineral supplements, respectively. Among screenees, response rates for the DHQ and the PLCO FFQ were 84% and 89%, respectively, and analyses of questions on portion size and supplement use showed few differences. These data indicated that the shorter FFQ was not better from the perspective of response rate and data quality, and that clarity and ease of administration may compensate for questionnaire length.

Evaluation of alternative approaches to assign nutrient values to food groups in food frequency questionnaires.

Although every food frequency questionnaire (FFQ) requires a nutrient database to produce nutrient intake estimates, it is often unclear how a particular database has been generated. Moreover, alternative methods for constructing a database have not been rigorously evaluated. Using 24-hour recalls from the 1994-1996 Continuing Survey of Food Intake by Individuals, the authors categorized 5,261 individual foods reported by 10,019 adults into 170 food groups consistent with line items on an FFQ. These food groups were used to generate 10 potential nutrient databases for a FFQ that varied by whether the authors 1) used means or medians, 2) did or did not consider age, 3) incorporated collapsing strategies for small age-gender-portion size cells, 4) excluded outliers in a regression, and 5) used weighted median nutrient density x age-gender-portion size-specific median gram weights (Block method). Mean error, mean squared error, and mean absolute error were calculated and compared across methods, with error being the difference in total observed (from recalls for each individual) and total estimated intake (from each of the 10 methods) for seven nutrients. Mean methods for assigning nutrients to food groups were superior to median approaches for all measurements. Among the mean methods, no single variation was consistently better.

Evaluation of 2 brief instruments and a food-frequency questionnaire to estimate daily number of servings of fruit and vegetables.

BACKGROUND: Measurement of fruit and vegetable intake is important in the surveillance of populations and in epidemiologic studies that examine the relations between diet and disease. Some situations require the use of brief dietary assessment tools. OBJECTIVE: Our objective was to evaluate the performance of 2 brief dietary assessment instruments, a 7-item standard screener and a new 16-item screener, and a complete food-frequency questionnaire (FFQ) in measuring total fruit and vegetable consumption. DESIGN: About 800 men and women from the National Institutes of Health-AARP Diet and Health Study completed an FFQ, 1 of the 2 screeners, and two 24-h dietary recalls. Fruit and vegetable intakes as measured by each screener and the FFQ were compared with estimated true usual intake by using a measurement-error model. RESULTS: Median daily servings of fruit and vegetables were underestimated by both screeners. The estimated agreement between true intake and the screener was higher for the new screener than for the standard screener and was higher for women than for men. The estimated agreement between true intake and the FFQ was higher than that for both screeners. Attenuation coefficients for the FFQ and screeners were comparable. CONCLUSIONS: For estimating median intakes of fruit and vegetables and the prevalence of recommended intakes being met, the use of screeners without appropriate adjustment is suboptimal. For estimating relative risks in the relations between fruit and vegetable intake and disease, screeners and this FFQ are similar in performance.

Nonvitamin, nonmineral dietary supplements: issues and findings from NHANES III.

The Commission on Dietary Supplement Labels encourages nutrition professionals to become knowledgeable about all dietary supplements. The Dietary Supplement Health and Education Act of 1995 (DSHEA) expanded the definition of dietary supplements beyond essential nutrients while distinguishing them from drugs or food additives. In order to give practical advice to consumers and policymakers, dietetics professionals need to understand the implications resulting from this less-restrictive regulatory environment for supplements. Dietetics professionals must also become familiar with claims made by manufacturers, retailers, and others regarding popular nonvitamin, nonmineral (NVNM) supplements, as well as usage prevalence and trends. However, NVNM supplements currently are classified inconsistently, and information on the prevalence of use is limited. Sales data suggest that total intake is increasing, and garlic and ginseng are consistently among the most popular supplements. Reported use of NVNM supplements in the third National Health and Nutrition Examination Survey was highest for garlic and lecithin. The data suggest associations of NVNM supplement use with age and more healthful lifestyles; however, there is also a reported link with higher alcohol consumption and obesity. Associations with education, income, region, and urbanization are not evident from the sales data. Standardized survey procedures regarding question phraseology, referent time period, and supplement categorization--along with use of representative samples--will improve our ability to assess supplement use, prevalence, and trends.

Comparison of the 60- and 100-item NCI-block questionnaires with validation data.

Large epidemiological studies often require short food frequency questionnaires (FFQ) to minimize the respondent burden or to control for confounding from dietary factors. In this analysis, we compared the extensively used National Cancer Institute-Block 60- and 100-item FFQs with one another and with usual intake as estimated from 12 days of validation data. The analysis focused on nutrients from different aspects of the diet, including energy, fat, saturated fat, beta-carotene, dietary fiber, and vitamin C. By use of an errors-in-variables analysis, the correlations of usual intake with the two types of FFQs for these nutrients were not different. Attenuation coefficients, a measure of misclassification error, for both FFQs were of similar magnitude and indicated that substantial attenuation of logistic regression coefficients would result from either FFQ. Our results confirm previous analyses describing the validity and utility of the 60-item FFQ (Epidemiology 1, 58-64, 1990) and indicate that it is essentially equivalent to the 100-item FFQ for epidemiological analyses of major nutrients.

Register of dietary assessment calibration-validation studies: a status report.

A register of dietary assessment calibration-validation studies was created to improve communication between investigators, avoid duplication of effort, and identify gaps in knowledge. Calibration-validation studies were defined as investigations in which the participants completed at least two different dietary measurements. A questionnaire soliciting descriptive information about such studies was widely distributed. Completed questionnaires were received from October 1993 through September 1994 and the data from them were entered into a computer database. Preliminary individual reports were mailed to all contributors in September 1994 for revision or updating. Responses received by the end of October 1994 were incorporated into the database. A status report was published in December 1994. The report includes descriptions of 84 studies, 15 summary tables, and 6 reference indexes. Of the 84 studies included, 44 (52%) were conducted in North America, 35 (42%) in Europe, 2 (2%) in South America, 2 (2%) in Asia, and 1 (1%) in Australia. Sixty-three of the 84 studies (75%) used food-frequency questionnaires, 52 (62%) used food records, 35 (42%) used one or more dietary recalls, 11 (13%) used biological measures, and 8 (10%) used diet histories. Plans for maintaining and updating the register are being developed.

Contribution of dieting to the inverse association between energy intake and body mass index.

OBJECTIVE: To examine the association of energy and % energy from fat with body mass index (BMI) and determine if self-reported dieting altered observed associations. DESIGN: Dietary intake data based on dietary recalls from four nonconsecutive days over a 1 year period were examined relative to BMI. The relation between energy intake and % energy from fat and BMI was examined by linear regression analysis. SUBJECTS: The sample included 1854 free-living women aged 19-50 years who participated in the 1985-6 Continuing Surveys of Food Intakes by Individuals conducted by the United States Department of Agriculture. RESULTS: Reported energy intake was inversely associated with BMI (regression coefficient (beta) = -0.001 24, standard error (s.e.) = 0.000 31). Controlling for low energy dieting alone reduced the inverse energy intake-BMI association by approximately 20% (beta = -0.001 00, s.e. = 0.000 31), compared to reductions of 16%, 13% and 10%, respectively, when health status, age and education were added individually to the energy intake-BMI linear regression. Physical activity, smoking status, % energy from fat and report of low fat dieting did not reduce the energy intake-BMI association. Controlling for nondietary factors related to BMI and potentially influencing energy intake reduced the inverse energy intake-BMI association by approximately 22% (beta = -0.000 97, s.e. = 0.00025). Further adjustment for low energy dieting on day 1 reduced the inverse energy intake-BMI association by 40% (beta = -0.000 74, s.e. = 0.000 26), suggesting that intermittent energy restriction was a significant factor in the reduced energy intake reported among overweight women. Percent energy from fat was not associated with BMI (beta = 0.049, s.e. = 0.025, P = 0.055). Exclusion of 37 women reporting poor health status further attenuated the inverse association between energy intake and BMI (beta = -0.000 64), s.e. = 0.000 26), while it strengthened the previously non-significant positive association between % energy from fat and BMI (beta = 0.062; s.e. = 0.024). CONCLUSION: Intermittent energy restriction appeared to be a significant factor in the reduced energy intake reported among overweight women in this sample. Adequate assessment of energy expenditure is required to correctly interpret the association of energy intake to body weight.

Improving food frequency questionnaires: a qualitative approach using cognitive interviewing.

In an attempt to improve data quality and ease of administration of standard self-administered food frequency questionnaires, various alternative approaches were tried for inquiring about frequency of consumption, portion size, seasonal intake, and food preparation. Evaluation consisted of a cognitive interviewing method in which respondents verbalize their thought process while completing several variations of a questionnaire. Interviewers observed and asked follow-up probe questions to evaluate problems or inconsistencies verbalized by respondents. Consensus and judgment by interviewers and observers suggested several problematic features of food frequency questionnaires: formatting of questions about frequency and portion size; computing average frequencies for aggregated food items or for foods eaten seasonally; comprehension of many items; and ordering of foods. These findings led to cognitive refinement and innovations, which included detailed questions regarding preparation or use of low-fat varieties or other alternatives to help better describe specifics of intake for some foods; questions on seasonal intake for several foods; inclusion of portion size ranges; and additional response categories for frequency of intake. Cognitive interviewing is an important step in pinpointing cognitive problems in dietary questionnaires.

Measles immunization of 2-year-olds in a rural southern state.

OBJECTIVE: To assess the measles vaccine coverage of 2-year-old children living in Mississippi during the national measles epidemic of 1989 and 1990. DESIGN: Survey of 2-year-olds randomly selected from the 1987 birth cohort. The status of measles-mumps-rubella (MMR) vaccination was determined by medical record reviews and family contacts. SETTING: A predominantly rural state in the southeastern United States with a large black minority population (35%) and a low per capital income ($9827 to $12,899). Approximately 80% of MMR immunizations are given by public health service nurses working in nine health districts. SUBJECTS: A total of 2450 preschool-aged children representing 6% of the 1987 birth cohort (n = 41,279). Three hundred forty-one children were considered ineligible, leaving 2109 in the final sample. MAIN OUTCOME MEASURES: Confirmed vaccination by the age of 2 years. Rates of immunization were calculated for the entire state, its health districts, and subgroups based on population density, per capita income, type of clinic visited, and race. RESULTS: The statewide immunization rate was 87% (95% confidence interval, 86% to 88%). Among the nine health districts, rates varied from 79% to 97% (median, 88%). They were similar for white and black children in each health district and within the state as a whole. The level of vaccine coverage was significantly higher in districts with lower population densities (89% vs 85%, P = .02) and in those with higher per capita incomes (89% vs 86%, P = .03). There were four minor outbreaks of measles during 1989 and 1990; half of the cases occurred in unimmunized children too young to receive the MMR vaccine. CONCLUSION: A high rate of measles immunization is attainable among 2-year-olds living in a rural state with a large black minority population and limited economic resources.

Dietary sources of fats and cholesterol in US children aged 2 through 5 years.

OBJECTIVES: This study of lipid intakes among preschool children (1) analyzed the contributions of 38 food groups to fat, saturated fat, and cholesterol intakes; (2) estimated the effects of food substitutions on intakes; and (3) examined demographic differences in food group intake and food group sources of these lipids. METHODS: The sample consisted of 547 children, aged 2 to 5 years, from the US Department of Agriculture's 1985 and 1986 Continuing Surveys of Food Intakes by Individuals. Dietary information for 4 nonconsecutive days throughout a year was used. All foods were classified into groups and the lipids contributed from each group were computed. RESULTS: Over 80% of the children consumed more total fat, saturated fats, and cholesterol than is recommended. The major source of total fat and saturated fats was whole milk; the major sources of dietary cholesterol were eggs and whole milk. Children's food consumption patterns differed by region of the country and race/ethnicity, providing opportunities to refine nutrition education interventions and evaluations. CONCLUSIONS: By substituting lower-fat foods for the major sources of saturated fats, significant reductions in preschool children's intakes of saturated fats, fat, and dietary cholesterol could be achieved.

"Eat for Health": a supermarket intervention for nutrition and cancer risk reduction.

OBJECTIVES: The results of an evaluation of "Eat for Health," a supermarket nutrition intervention, are presented. The study tested whether such a program could be successfully carried out and whether it could effect changes in knowledge, attitudes, and food purchasing behavior in line with nutrition and cancer risk reduction guidelines. METHODS: The evaluation consisted of an in-store monitoring element, an in-store and telephone consumer survey, and an analysis of sales data on selected foods. A matched-pair design, using a total of 40 stores in the intervention and comparison groups, was used. RESULTS: The intervention was successfully implemented and had limited success in changing some food purchasing behaviors. There appeared to be no effect on knowledge and attitudes except for increased awareness of a link between diet and cancer and of the program itself. CONCLUSIONS: Despite the intervention's success, limitations of the consumer survey and sales data analyses and the continuing diffusion of nutrition messages throughout society make it difficult to specify the impact of this program on consumer nutrition knowledge and behaviors.

Practice and attitudes of primary care physicians in a rural southern state concerning HIV/AIDS patients.

In preparing for the development of a plan of care for persons with AIDS and other HIV related conditions, the HIV Services Planning Program, a joint effort of the Department of Family Medicine of the University of Mississippi Medical Center and the Bureau of Preventive Health of the Mississippi State Department of Health, conducted a survey of all primary care physicians throughout the state of Mississippi. The purpose of the survey was to determine health care services provided to persons with HIV/AIDS. Specific areas of interest included: (a) type of medical specialty; (b) location of primary practice; (c) services provided for persons with HIV/AIDS; and (d) utilization of universal blood and body fluid precautions, i.e., barrier techniques. Descriptive statistics were utilized in analyzing responses.

Comparison of two dietary questionnaires validated against multiple dietary records collected during a 1-year period.

The validity of two dietary history questionnaires was examined, one the Health Habits and History Questionnaire (HHHQ) developed by Block et al and the other a questionnaire developed by investigators at the University of Michigan (UM). The reference data consisted of the mean of four 4-day dietary records and recalls collected for 1 year before administration of the questionnaires. The sample of 85 persons included black and white men and women aged 25 to 50 years. The HHHQ was entirely self-administered; the UM questionnaire had both self- and interviewer-administered components. The HHHQ group means were similar to food record estimates for energy and most nutrients, whereas the UM questionnaire produced overestimates for energy and all nutrients examined. Correlations ranged from .31 to .60 (median = .48) for the UM questionnaire and from .42 to .68 (median = .57) for the HHHQ. Use of respondent-reported portion sizes with the HHHQ produced higher correlations than use of investigator-determined "standard" portion sizes (median r = .43 vs .57). Food frequency questionnaires can provide useful nutrient data for individuals as well as groups.