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

Abstract

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-speci®c 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-speci®c 85th and 95th percentiles of NHANES I, while the cut-off for overweight was a BMI 95th percentiles. Age-speci®c sex differences were compared using independent samples t-tests. Secular changes for body size were estimated by comparing age-and sex-speci®c means for stature, mass, and the BMI in the present study and two previous studies in 1955 and 1989. RESULTS: No statistically signi®cant differences were observed between sexes within age groups. In both sexes, mean age-speci®c stature appeared to be relatively stable around the 50th percentile of US reference values. Mean age-speci®c mass appeared to be relatively stable between the 50th and 90th percentiles of the reference values, while the mean BMI tended to¯uctuate 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 kgadecade in younger boys and girls, and about 3 kgadecade in older boys and girls between 1955 and 1997. The estimated rate of secular change in the BMI was about 0.5 ± 1.0 unitsadecade between 1955 and 1997, while that for stature was about 2 cmadecade between 1955 and 1997. CONCLUSIONS: The results are consistent with recent ®ndings 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.

Growth and obesity in 7-year-old Croatian children: secular changes from 1991 to 2008

“…The improvement in social and economic conditions and the availability of health care probably still have a positive effect on trends in secular changes in body height in boys and girls in the observed population. The results of this study also show a parallel secular rise in values of body weight and BMI, in line with previous studies [8,22]. In countries with intensive development, secular growth of BMI values has been noticed of 0.57 kg/m 2 in boys and 0.58 kg/m 2 in girls [5].…”

Secular changes in stature and body mass index for Chinese youth in sixteen major cities, 1950s–2005

“…Since then, dramatic secular increases, both in stature and BMI have been observed. Though dissimilar with that in developed countries (secular changes in stature diminished in the latest decades), a same trend of increasing weight disproportionate to stature occurred at all ages in recent 20 years, especially for adolescents (Eisenmann et al, 2000;He et al, 2000;Mark et al, 2000). On account of the recent increases in prevalence of childhood obesity, Ji and WGOC (2005) analyzed the growth pattern of BMI for the Chinese urban youth during 1985-2005, and found that BMI increased at any given percentile for both sexes, but strikingly more at the upper end of the distribution, e.g.…”

The Nutrition Transition in American Indians

“…In Navajo youth compared between 1955 and 1997, BMI increased 0.5 to 1.0 units per decade to prevalence rates of 41% at risk of overweight, and a mean BMI near the 85th percentile (Eisenmann et al, 2000). In 1994, among 527 Mohawk children 6 to 11 years of age, only 7% were underweight, but 31% were at risk of or overweight (Potvin et al, 1999).…”