Effects of age on validity of self-reported height, weight, and body mass index: findings from the Third National Health and Nutrition Examination Survey, 1988-1994

OBJECTIVE

To compare self-reported to measured heights and weights of adults examined in the Third National Health and Nutrition Examination Survey (NHANES III), and to determine to what extent body mass index (BMI) calculated from self-reported heights and weights affects estimates of overweight prevalence compared with BMI calculated from measured values.

DESIGN

A complex sample design was used in NHANES III to obtain a nationally representative sample of the US civilian, noninstitutionalized population. During household interviews, survey respondents were asked their height and weight. Trained health technicians subsequently measured height and weight using standardized procedures and equipment.

SUBJECTS

The analytical sample consisted of 7,772 men and 8,801 women 20 years old and older.

STATISTICAL ANALYSES PERFORMED

Only persons with measured and self-reported heights and weights were included in the analysis, and statistical sampling weights were applied. t Tests, Pearson product moment correlation coefficients, sensitivity, and specificity analyses were used to determine the validity of self-reported measurements and prevalence estimates of overweight, defined as BMI of 25 or greater.

RESULTS

Age is an important factor in classifying weight, height, BMI, and overweight from self-reports. Statistically significant differences were found for the mean error (measured-self-reported values) for height and BMI that were notably larger for older age groups. For example, the mean error for height ranged from 2.92 to 4.50 cm for women and from 3.06 to 4.29 cm for men, 70 years and older. Despite the high correlation between measured and self-reported data, the prevalence of overweight calculated from measured values was higher than that calculated from self-reported values among older adults. When calculated with self-reported height, BMI was one unit lower than when calculated from measured height for persons > or = 70 years. Specificity was high but sensitivity decreased with increasing age cohorts. Regression equations are provided to determine actual height from self-reported values for older adults. CONCLUSION/APPLICATIONS: Self-reported heights and weights can be used with younger adults, but they have limitations for older adults, ages > or = 60 years. In research studies and in clinical settings involving older adults, failure to measure height and weight can result in subsequent misclassification of overweight status. Therefore, registered dietitians are encouraged to obtained a measured weight and height using a calibrated scale and stadiometer.

Descriptive anthropometric reference data for older Americans

OBJECTIVE

To present selected anthropometric data derived from adults aged 60 years and older examined in the third National Health and Nutrition Examination Survey (NHANES III).

DESIGN

NHANES III used a complex, stratified, multistage, probability cluster sample design to obtain a nationally representative sample of the US civilian, noninstitutionalized population. Persons aged 60 years and older, Mexican-Americans, and African-Americans were oversampled to produce more reliable estimates for these groups. Trained technicians measured height, weight, skinfold thickness, and circumferences using standardized procedures.

SUBJECTS

A total of 5,700 persons aged 60 years and older, and 1,861 persons aged 50 to 59 years.

STATISTICAL ANALYSES PERFORMED

Mean and selected percentiles for body weight, body mass index, triceps skinfold thickness, mid upper arm circumference, and arm muscle circumference were calculated by gender, race/ethnicity, and 3 age categories. Weight (lb) per height (in) tables were generated for men and women by age group.

RESULTS

Mean body weight was lowest for persons aged 80 years and older. A decline in body mass index occurred that paralleled the direction and magnitude of the progressive decrease observed in weight. Muscle loss with increasing age, as indicated by arm muscle circumference, appeared to be greater among men than women.

APPLICATIONS/CONCLUSIONS

In addition to being relatively simple, quick, and inexpensive, anthropometry is the most reliable and specific indicator of malnutrition in the older adult population. The cross-sectional reference data provided can be used by dietitians to interpret anthropometric measurements of persons aged 60 years and older.

Dietary antioxidant intake and its association with cognitive function in an ethnically diverse sample of US adults

BACKGROUND

Dietary antioxidants can inhibit reactions accompanying neurodegeneration and thus prevent cognitive impairment. We describe associations of dietary antioxidants with cognitive function in a large biracial population, while testing moderation by sex, race, and age and mediation by depressive symptoms.

METHODS

This was a cross-sectional analysis of 1274 adults (541 men and 733 women) aged 30 to 64 years at baseline (mean [standard deviation] = 47.5 [9.3]) in the Healthy Aging in Neighborhoods of Diversity Across the Lifespan Study, Baltimore city, MD. Cognitive performance in the domains of memory, language/verbal, attention, spatial, psychomotor speed, executive function, and global mental status were assessed. The 20-item Center for Epidemiologic Studies Depression Scale was used to measure depressive symptoms. Dietary intake was assessed with two 24-hour recalls, estimating daily consumption of total carotenoids and vitamins A, C, and E per 1000 kcal.

RESULTS

Among key findings, 1 standard deviation (∼ 2.02 mg/1000 kcal) higher vitamin E was associated with a higher score on verbal memory, immediate recall (β = +0.64 [0.19], p = .001), and better language/verbal fluency performance (β = +0.53 [0.16], p = .001), particularly among the younger age group. Women with higher vitamin E intake (β = +0.68 [0.21], p = .001) had better performance on a psychomotor speed test. The vitamin E-verbal memory association was partially mediated by depressive symptoms (proportion mediated = 13%-16%).

CONCLUSIONS

In sum, future cohort studies and dietary interventions should focus on associations of dietary vitamin E with cognitive decline, specifically for domains of verbal memory, verbal fluency, and psychomotor speed.

Dietary Protein Intake and Overall Diet Quality Are Associated with Handgrip Strength in African American and White Adults

OBJECTIVE

To determine the association of handgrip strength (HS) with protein intake, diet quality, and nutritional and cardiovascular biomarkers in African American and White adults.

DESIGN

Cross-sectional wave 3 (2009-2013) of the cohort Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) study.

PARTICIPANTS

Socioeconomically diverse urban population of 2,468 persons aged 33 to 71 years.

MEASUREMENTS

Socio-demographic correlates, dietary intakes and biomarkers, HS, physical performance measures were collected. HS was measured using a dynamometer with the dominant hand. Functional measures included chair, tandem, and single leg stands. Two 24-hour recalls were collected using the US Department of Agriculture Automated Multiple Pass Method. The total protein intake and diet quality, evaluated by adherence to the DASH eating plan and Healthy Eating Index-2010, were calculated. Biomarkers included nutritional anemia, and serum levels of albumin, cholesterol, magnesium, and glucose.

RESULTS

The mean ±SE age of the sample was 52.3±0.2 years. Approximately 61% were African American and 57% were women. The mean ±SE HS of women was 29.1±0.2kg and for men was 45.9±0.4 kg. Protein, gm, per kg body weight for the women was 0.94±0.02 compared to 1.16 ±0.02 for men. After adjusting for socio-demographic factors, hypertension, and diabetes, HS/BMI ratio was significantly associated with protein intake per kg body weight (p<0.001) and diet quality, assessed by either the DASH adherence (p=0.009) or Health Eating Index-2010 (p=0.031) scores. For both men and women, participants in the upper tertile of HS maintained a single leg and tandem stances longer and completed 5 and 10 chair stands in shorter time compared to individuals in the lower HS tertile. Of the nutritional status indicators, the percent of men in the upper HS tertile with low serum magnesium and albumin, was significantly lower than those in the lower HS tertile [magnesium,7.4% vs 16.1%; albumin, 0.4% vs 4.5%]. The only difference observed for women was a lower percent of diabetes (14.4% for the upper HS tertile compared to 20.5% for the lower HS tertile.

CONCLUSIONS

The findings confirm the role of protein and a healthful diet in the maintenance of muscle strength. In this community sample, HS was significantly associated with other physical performance measures but did not appear to be strongly associated with indicators of nutritional risk. These findings support the use of HS as a proxy for functional status and indicate the need for research to explore its role as a predictor of nutritional risk.

Update on nutrition monitoring activities in the United States

This article provides an overview of planned and proposed nutrition monitoring activities of the National Nutrition Monitoring and Related Research (NNMRR) Program. Key provisions of the NNMRR Act of 1990 are described, including the roles and responsibilities of the Interagency Board of Nutrition Monitoring and Related Research (IBNMRR) and the National Nutrition Monitoring Advisory Council and the development of the Ten-Year Comprehensive Plan. The Plan, which was developed under the guidance of the IBNMRR and reviewed by the National Nutrition Monitoring Advisory Council, is the basis for planning and coordinating the monitoring activities of 22 federal agencies. Also discussed are the resources generated from nutrition monitoring activities, from publications to conferences, that are available to dietitians and nutritionists. Professionals view the scientific reports that describe the nutritional status of the US population and the directories of federal and state monitoring activities as valuable resources. Suggestions from users of nutrition monitoring data related to their information and research needs have been extremely helpful to federal agencies in the development of future monitoring publications and the Ten-Year Comprehensive Plan. Continued communication between dietitians and the federal agencies responsible for the NNMRR Program is important.