摘要:

AbstractKernel regression is a nonparametric procedure that provides good approximations to individual serial data. The method is useful and flexible when a parametric method is inappropriate due to restricted assumptions on the shape of the curve. In the present study, we compared kernel regression in fitting human stature growth with two models, one of which incorporates the possible existence of the midgrowth spurt while the other does not. Two families of mathematical functions and a nonparametric kernel regression were fitted to serial measures of stature on 227 participants enrolled in the Fels Longitudinal Study. The growth parameters that describe the timing, magnitude, and duration of the growth spurt, such as midgrowth spurt and pubertal spurts, were derived from the fitted models and kernel regression for each participant. The two parametric models and kernel regression were compared in regard to their overall goodness of fit and their capabilities to quantify the timing, rate of increase, and duration of the growth events. The Preece‐Baines model does not describe the midgrowth spurt. The dervied growth parameters from the Preece‐Baines model show an earlier onset and a longer duration of the pubertal spurt, and a slower increase in velocity. The kernel regression with bandwidth 2 years and a second‐order polynomial kernel function yields relatively good fits compared with the triple logistic model. The derived biological parameters for the pubertal spurt are similar between the kernel regression and the triple logistic model. Kernel regression estimates an earlier onset and a more rapid increase of velocity for the midgrowth

ISSN:1042-0533    

DOI:10.1002/ajhb.1310040112

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractThe height and weight of 28,752 urban and 10,557 rural individuals aged birth to 18 years were measured as part of a cross‐sectional national survey (Project Venezuela) between 1981 and 1986. The Preece‐Baines model 1 was fitted to the means; pooled residual mean squares of 0.21 and 0.13 in height and 0.44 and 0.13 in weight, for boys and girls respectively, indicated a good fit. Derived means and biological parameters were compared. The nutritional status of 18,849 children aged birth to 8 years was assessed using the WHO‐recommended NCHS/CDC 3rd or 10th and 90th centiles as cut‐off points for weight for height, weight for age, and height for age. Attest for proportions was used to test significance. Urban children were taller and heavier than their rural counterparts; differences were evident after age 2 and maximal at 14 years in boys and 12 years in girls, due to differences in tempo, although part of the differences persist into adulthood. Prevalences of wasting and stunting were 3.5% and 10.5% higher in rural children and overweight was 3.6% higher in urban children, significantly so in height for age. A mixed nutritional problem is present in Venezuelans, with a prevalence of stunting greater than that of wasting and a prevalence of overweight greater in urban children. Urban–rural differences in growth persisted into adulthood in boys, while rural girls were similar to urban girls at the end

ISSN:1042-0533    

DOI:10.1002/ajhb.1310040113

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractValidity generalization was used to ascertain the generalizability of skinfolds as measures of body density. A literature search was conducted to locate studies employing skinfolds as predictors of body density using hydrostatic weighing as the criterion test. The sites examined included the triceps, subscapula, suprailiac, abdomen, front thigh, midaxillary, and the log sum of the biceps, triceps, suprailiac, and subscapula. Results indicated that no single sites were generalizable across all subjects; however, the log sum of the four sites was generalizable. For adult males, the suprailiac and midaxillary sites were generalizable, while the subscapular site was generalizable for women. No sites were generalizable for boys, while the triceps site was generalizable for girls. Suggestions are provided for additional research.

ISSN:1042-0533    

DOI:10.1002/ajhb.1310040114

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

ISSN:1042-0533    

DOI:10.1002/ajhb.1310040115

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

ISSN:1042-0533    

DOI:10.1002/ajhb.1310040116

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

ISSN:1042-0533    

DOI:10.1002/ajhb.1310040117

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

ISSN:1042-0533    

DOI:10.1002/ajhb.1310040118

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

ISSN:1042-0533    

DOI:10.1002/ajhb.1310040119

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

ISSN:1042-0533    

DOI:10.1002/ajhb.1310040120

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

ISSN:1042-0533    

DOI:10.1002/ajhb.1310040121

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY