The Navajo Health and Nutrition Survey: research that can make a difference

Health behaviors and risk factors among American Indians and Alaska Natives, 2000-2010

OBJECTIVES

We provided contextual risk factor information for a special supplement on causes of death among American Indians and Alaska Natives (AI/ANs). We analyzed 11 years of Behavioral Risk Factor Surveillance System (BRFSS) data for AI/AN respondents in the United States.

METHODS

We combined BRFSS data from 2000 to 2010 to determine the prevalence of selected risk factors for AI/AN and White respondents residing in Indian Health Service Contract Health Service Delivery Area counties. Regional prevalence estimates for AI/AN respondents were compared with the estimates for White respondents for all regions combined; respondents of Hispanic origin were excluded.

RESULTS

With some regional exceptions, AI/AN people had high prevalence estimates of tobacco use, obesity, and physical inactivity, and low prevalence estimates of fruit and vegetable consumption, cancer screening, and seatbelt use.

CONCLUSIONS

These behavioral risk factors were consistent with observed patterns of mortality and chronic disease among AI/AN persons. All are amenable to public health intervention.

Children's safety on American Indian farms: information and recommendations

It is estimated that 1.2 million youth younger than age 20 live on farms; American Indian children constitute an important but understudied subset of this at-risk group. Despite documented risks of injuries and death among children who live and work on farms and a descending trend in the overall reported fatalities among youth who live and/or work on farms, very little is known about the agriculture-related injury and fatality experience of American Indian youth. Limited data indicate that drowning, motor vehicles, and poisonings are leading causes of unintentional mortality and morbidity for this group, although the attribution to agricultural exposure is not evident. The scant available data indicate a need to look more closely at agricultural work, bystander exposures, and other farm events that put American Indian youth at risk of illness, injury, or death compared to factors more fully reported for majority youth in the agriculture population, in order to guide intervention and prevention programs that are appropriate and acceptable to this vulnerable population.

Enhancing American Indian and Alaska Native health research: a multi-faceted challenge

The quality, relevance, timeliness, and impact of public health research among American Indians and Alaska Natives (AIAN) has improved markedly over the last several decades. These advances are attributable to the more careful fit between investigative methods and field exigencies, to the increased presence of Native scientists among research teams, to greater emphasis on meaningful collaboration between researchers and participating communities, and to new Federal investments in the infrastructure that supports health research within this special population. This paper describes the lessons learned from this recent progress, and highlights opportunities to promote further gains as well as continuing needs in developing our capacity to conduct policy relevant AIAN health research.

Access, relevance, and control in the research process: lessons from Indian country

OBJECTIVE

To illustrate successful strategies in working with American Indian (AI) and Alaska Native (AN) communities in aging and health research by emphasizing access, local relevance, and decision-making processes.

METHODS

Case examples of health studies involving older AIs (greater than or equal to 50 years) among Eastern Band Cherokee Indians, a federally recognized reservation; the Cherokee Nation, a rural, nonreservation, tribal jurisdictional service area; and Lakota tribal members living in Rapid City, South Dakota.

RESULTS

Local review and decision making reflect the unique legal and historical factors underpinning AI sovereignty. Although specific approval procedures vary, there are common expectations across these communities that can be anticipated in conceptualizing, designing, and implementing health research among native elders.

CONCLUSIONS

Most investigators are unprepared to address the demands of health research in AI communities. Community-based participatory research in this setting conflicts with investigators' desire for academic freedom and scientific independence. Successful collaboration promises to enhance research efficiencies and move findings more quickly to clinical practice.

Cultural specificity and comparison in psychiatric epidemiology: walking the tightrope in American Indian research

Increasingly, the mental health needs of populations are measured using large-sample surveys with standardized measures and methods. Such efforts, however, rarely include sufficient number of smaller, culturally defined populations to draw defensible conclusions about their needs. Furthermore, without some adaptation, the standardized methods and measures may yield invalid results in such populations. Using a recently completed psychiatric epidemiology and services study with American Indian populations as a case example, this paper outlines issues facing epidemiologists working in such culturally diverse contexts. The issues discussed include the following: (1) persuading the scientific community and potential sponsors that work with distinct or culturally defined populations is important; (2) framing research questions and activities to meet the needs of communities; (3) defining a population of inference; (4) balancing the needs for comparability and cultural specificity; (5) maximizing scientific validity in light of the challenges in sample acquisition; and (6) developing and implementing data collection methods that uphold scientific standards but are also realistic given the context. The authors draw on their experiences--most recently in the American Indian Service Utilization, Psychiatric Epidemiology, Risk and Protective Factors Project (AI-SUPERPFP)--to illustrate these issues and suggest ways to address each. A goal of this paper is to challenge those invested in conducting culturally valid epidemiologic work in such populations to better articulate the nature of these efforts.

Growth and overweight of Navajo youth: secular changes from 1955 to 1997

OBJECTIVE

To examine the growth status, prevalence of risk of overweight and of overweight, and secular changes in growth status in Navajo youth from 1955 to 1997.

SUBJECTS

526 (256 males, 270 females) Navajo children 6-12 y of age.

MEASUREMENTS

Stature and mass were measured and the body mass index (BMI) was calculated.

ANALYSIS

All three variables were plotted relative to age- and sex-specific US reference data and the prevalence rates for risk of overweight and of overweight were estimated using the BMI as the criterion. The cut-off for the risk of overweight was the age- and sex-specific 85th and 95th percentiles of NHANES I, while the cut-off for overweight was a BMI>/=95th percentiles. Age-specific sex differences were compared using independent samples t-tests. Secular changes for body size were estimated by comparing age- and sex-specific means for stature, mass, and the BMI in the present study and two previous studies in 1955 and 1989.

RESULTS

No statistically significant differences were observed between sexes within age groups. In both sexes, mean age-specific stature appeared to be relatively stable around the 50th percentile of US reference values. Mean age-specific mass appeared to be relatively stable between the 50th and 90th percentiles of the reference values, while the mean BMI tended to fluctuate about the 85th percentile. Approximately 41% of the Navajo boys and girls 6-12 y of age had BMIs >/=85th percentiles of US reference data. Compared to corresponding data on Navajo youth in 1955 and 1989, the current sample was larger in mass and the BMI. The estimated rate of secular change in mass was about 1.5 kg/decade in younger boys and girls, and about 3 kg/decade in older boys and girls between 1955 and 1997. The estimated rate of secular change in the BMI was about 0.5-1.0 units/decade between 1955 and 1997, while that for stature was about 2 cm/decade between 1955 and 1997.

CONCLUSIONS

The results are consistent with recent findings on the Navajo Health and Nutrition Survey that overweight is a serious public health concern across the lifespan in the Navajo, and that the problem begins in childhood. Furthermore, Navajo children appear to be heavier than about a decade ago. International Journal of Obesity (2000) 24, 211-218

Assessing food selection in a health promotion program: validation of a brief instrument for American Indian children in the southwest United States

OBJECTIVE

Brief dietary assessment instruments are needed to evaluate behavior changes of participants in dietary intervention programs. The purpose of this project was to design and validate an instrument for children participating in Pathways to Health, a culturally appropriate, cancer prevention curriculum.

DESIGN

Validation of a brief food selection instrument, Yesterday's Food Choices (YFC), which contained 33 questions about foods eaten the previous day with response choices of yes, no, or not sure. Reference data for validation were 24-hour dietary recalls administered individually to 120 students selected randomly.

SUBJECTS

The YFC and 24-hour dietary recalls were administered to American Indian children in fifth- and seventh-grade classes in the Southwest United States.

STATISTICAL ANALYSES PERFORMED

Dietary recalls were coded for food items in the YFC and results were compared for each item using percentage agreement and the kappa statistic.

RESULTS

Percentage agreement for all items was greater than 60%; for most items it was greater than 70%, and for several items it was greater than 80%. The amount of agreement beyond that explained by chance (kappa statistic) was generally small. Three items showed substantial agreement beyond chance (kappa > or = 0.6); 2 items showed moderate agreement (kappa = 0.40 to 0.59) most items showed fair agreement (kappa = 0.20 to 0.39). The food items showing substantial agreement were hot or cold cereal, low-fat milk, and mutton or chile stew. Fried or scrambled eggs and deep-fried foods showed moderate agreement beyond chances.

CONCLUSIONS

Previous development and validation of brief food selection instruments for children participating in health promotion programs has had limited success. In this study, instrument-related factors that apparently contributed to poor agreement between data from the YFC and 24-hour dietary recall were inclusion of categories of foods vs specific foods; food knowledge, preparation, and vocabulary, item length, and overreporting of attractive foods. Collecting and scoring the 24-hour recall data may also have contributed to poor agreement. Further development of brief instruments for evaluating changes in children's behavior in dietary programs is necessary. Factors related to the YFC that need further development may be issues that are also important in the development of effective, brief dietary assessments for children as individual clients or patients.