Body mass index, weight change and mortality in the elderly. A 15 y longitudinal population study of 70 y olds.

OBJECTIVE: To examine the relationship between body mass index (BMI) at age 70, weight change between age 70 and 75, and 15 y mortality. DESIGN: Cohort study of 70-y-olds. SETTING: Geriatric Medicine Department, G?teborg University, Sweden. SUBJECTS: A total of 2628 (1225 males and 1403 females) 70-y-olds examined in 1971--1981 in Gothenburg, Sweden. RESULTS: The relative risks (RRs) for 15 y mortality were highest in the lowest BMI quintiles of males 1.20 (95% CI 0.96--1.51) and females 1.49 (95% CI 1.14--1.96). In non-smoking males, no significant differences were observed across the quintiles for 5, 10 and 15 y mortality. In non-smoking females, the highest RR (1.58, 95% CI 1.15--2.16) for 15 y mortality was in the lowest quintile. After exclusion of first 5 y death, no excess risks were found in males for following 5 and 10 y mortality across the quintiles. In females, a U-shaped relation was observed after such exclusions. BMI ranges with lowest 15 y mortality were 27--29 and 25--27 kg/m(2) in non-smoking males and females, respectively. A weight loss of > or = 10% between age 70 and 75 meant a significantly higher risk for subsequent 5 and 10 y mortality in both sexes relative to individuals with 'stable' weights. CONCLUSION: Low BMI and weight loss are risk factors for mortality in the elderly and smoking habits did not significantly modify that relationship. The BMI ranges with lowest risks for 15 y mortality are relatively higher in elderly. Exclusion of early deaths from the analysis modified the weight-mortality relationship in elderly males but not in females.     

Socio-economic differences in height and body mass index of children and adults living in urban areas of Karachi, Pakistan

OBJECTIVE: To study the socio-economic differences in height and body mass index (BMI) in urban areas of Karachi. DESIGN: A comparative study was undertaken to compare the heights and BMIs of adults and children belonging to three distinctively different income groups living in urban areas of Karachi. SETTING: Data was collected from families living in small, medium and large houses located in the authorised urban residential areas of Karachi. SUBJECTS: A total of 600 families, 200 from each income group, were included in the study. Anthropometric measurements of 1296 females and 1197 males of different ages were taken. METHODS: All the housewives were interviewed to collect socio-demographic information. Height and weight of all the available family members were measured. In order to determine the socio-economic difference in height status, the mean height in cm of adults was compared. For children (2-17 y) means of height-for-age Z-scores determined on the basis of NCHS reference values were compared. For studying the weight status the BMI of all the respondents was calculated and they were grouped into categories of under-, normal or overweight according to the NCHS recommended cut-off points. For adult men and women BMI values <18.5 kg/m(2) indicated underweight and >25 kg/m(2) indicated overweight. Among children, those having BMI values below the 5th percentile of the NHANES III reference values were categorised as underweight and those above the 95th percentile were termed overweight. RESULTS: Height status improved with income level among adults and children of both sexes. Among males the difference in weight status was significant only among 2 to 18-y-olds (P<0.05 in each case). The rate of overweight among 2 to 18-y-old males was significantly higher (P=0.004) at the middle-income level (15%) as compared to low or high income. The rate of underweight was significantly higher (P=0.025) at the low-income level among 2 to 18-y-old males (31%, 21% and 22% at low-, middle- and high-income levels, respectively). Among females, rates of underweight were not significantly different at any age. Rates of overweight increased significantly (P=0.048) with income level among 41 to 60-y-old women (38%, 53% and 60% at low-, middle- and high-income levels, respectively). CONCLUSION: Chronic undernutrition as indicated by deficit in height decreased with increasing income level. Socio-economic differences in weight status were not uniform among various age-sex groups. The influence of increasing affluence is likely to be seen both in the form of increased obesity among older females and underweight among children. Differing patterns of association between income and weight status among male and female children need to studied further with more accurate birth records, so as to further clarify the situation. In terms of prevention of nutrition-related disorders both problems of under- and over-nutrition need to be addressed.     

Body mass index from childhood to middle age: a 50-y follow-up.

The tracking of body mass index (BMI) over a 50-y period in a longitudinal study was examined by using both correlation coefficients and the Foulkes-Davis tracking index. Over the long term, BMIs before maturity were poor predictors of middle-aged BMI status in females but were good predictors in males. The correlation between females' BMI in childhood and their BMIs at two points during middle age (40 and 50 y) was zero; in males it was r = 0.36 and 0.41, respectively. Between-age correlations were high (P less than 0.0001) for both sexes, reflecting stability in BMI over the shorter term (less than or equal to 10 y). The tracking of BMI (with the Foulkes-Davis tracking index) from childhood to middle age was better for males than for females (P less than 0.1). Linear-regression analysis was also used to assess the predictability of relative body size in middle age from earlier measures; BMI in childhood accounted for 0% of the variance in females and 17% in males. We conclude that the prediction of ponderosity in middle age from BMIs early in life is more reliable for males than for females.     

Height, weight and skinfold thickness of Michigan adults.

Height, weight, and selected skinfold measurements were taken on 544 Michigan males and 557 females age 18 and over. Mean body weight showed a tendency to increase with age for both sexes up to age 64 while mean height progressively decreased from its maximum at age 18-24 years. Between ages 18 and 64 years, mean triceps skinfold thickness of men increased 10 per cent, female triceps skinfolds 50 per cent. Mean subscapular skinfold values rose consistently with age for both sexes. Comparison of these findings with those from earlier national studies suggest that Michigan adults are heavier and fatter but no taller than other US adults.     

The Association Between Body Mass Index in Adolescence and Obesity in Adulthood

PURPOSE: This study used data from the National Longitudinal Study of Youth 1979 to examine the association between body mass index (BMI) in adolescence and obesity in adulthood. METHODS: Measurements of height and weight from 1981 and 2002 were used to calculate BMI for a cohort of 1309 adolescents at baseline and during adulthood. Associations between BMI at age 16/17 and obesity (BMI > or =30) at age 37/38 were analyzed using logistic regression analysis. RESULTS: When the predicted probability of adult obesity equaled 0.5, the point on the adolescent BMI distribution was close to the 85th percentile for both sexes (83rd percentile for females and 86th percentile for males). Among adolescents with a BMI in the 85th-<95th percentile, 62% of the males and 73% of the females became obese adults. Among those with a BMI > or =95th percentile, 80% of the males and 92% of the females became obese adults. Versus those with a BMI <85th percentile, those with a BMI in the 85th-<95th percentile were more likely to be obese (odds ratio = 7 for males, 11 for females) as adults, and those with a BMI > or =95th percentile were most likely to be obese (odds ratio = 18 for males, 49 for females) as adults. CONCLUSION: Adolescents with a BMI > or =85th percentile are at elevated risk for obesity in adulthood. To prevent the development of obesity and its associated health risks, population-based efforts combined with targeted interventions for these high-risk adolescents are needed.     

Long-term memory of body weight and past weight satisfaction: a longitudinal follow-up study

Recalled body weight and self-reported current weight were validated in a longitudinal study population by comparing recalls at 50 y to actual measures taken at ages 18, 30, 40, and 50 y. Recalled body weights were also compared with reported desired weights at these same ages. Self-reported weights at 50 y were equally accurate for both males and females; the mean reporting underestimate was -1.98 kg for males and -1.86 kg for females. Males' self reports at age 50 y were influenced by years of education (P less than 0.005) and current body size (P less than 0.0001) whereas females' were not. Correlations between recall of past weights and measured weights ranged from r = 0.87 at 18 y to 0.95 at 40 y. Recalls of past body weight were not significantly influenced by the passage of time, the number of years of education, or the accuracy of current weight reports. Current body size (wt/ht2) was significantly associated with life-time weight dissatisfaction in both sexes (P less than 0.0005).     

Body composition and nutrient intake of hypertensive elders and middle-aged men and women in Nigeria

Body composition of eighty hypertensive patients (43 middle-aged, 30-59 years and 37 elders, 60-80 years) was determined by anthropometry alongside their dietary intake. The mean body weight and height of female elders were 54.1 +/- 14.6 kg and 157.0 +/- 7.0 cm while that of male elders were 61.8 +/- 13.5 kg and 167.1 +/- 9.0 cm. Corresponding values for middle-aged subjects were also determined. The middle-aged subjects were heavier and taller than the elders in both sexes. Among the elders BMI values 21.7 (females) and 22.1 (males) were normal, but the female had higher percentage body fat (28.0 +/- 0.1%) than males (20.8 +/- 5.2%). Other body composition parameters determined included lean body mass, optimum body weight, body water, skin-fold thickness and arm muscle diameter. BMI was significantly correlated with high blood pressure. The mean energy and nutrient intake of the subjects were inadequate except for the female elders.     

Waist circumference values in Spanish children--gender related differences.

OBJECTIVE: To obtain reference values of the waist circumference in Spanish children, and to investigate their dependence on age and gender. DESIGN: Cross-sectional study. SETTING: General school-age population. SUBJECTS: A representative sample of the schools in Zaragoza, Spain, was drawn from seven schools. The population selected comprised 1728 children with ages ranging from 6.0-14.9y. Of the original sample, 368 children (21.29%) were excluded because of chronic diseases or refusal. Finally, 1360 children and adolescents: 701 boys and 659 girls, were studied. INTERVENTIONS: Waist and hip circumferences were measured with an unelastic tape. RESULTS: Waist circumference tended to be higher in males than in females and this difference was significant after 11.5y. In general, hip circumference was higher in females than in males (statistically significant differences at 7.5, 10.5, 12.5 and 13.5 y). In general, percentile values of waist circumference were higher in males than in females, especially after 12.5 y. Difference between males and females on percentile 95 at 14.5 y was 7.6 cm. Hip was greater than waist in both sexes, and the two curves run nearly parallel in males. In females, while hip enlarges continuously, waist shows the reverse tendency between 11.5 and 14.5 y. CONCLUSIONS: Waist circumference showed higher values in boys than in girls, especially after 11.5 y, and waist values increase with age both in males and females. These findings justify the use of age and gender specific reference standards.     

Body composition estimated by bioelectrical impedance in the Swedish elderly. Development of population-based prediction equation and reference values of fat-free mass and body fat for 70- and 75-y olds

OBJECTIVE: To develop a bioelectrical impedance (BIA) prediction equation for fat-free mass (FFM(BIA)) and present reference values of FFM and body fat (BF) for healthy Swedish elderly from population-based representative samples. SUBJECTS: This study is based on 823 (344 males, 479 females) participants from two systematic samples of birth cohorts in G?teborg aged 70 (cohort H70V, 201 males and 299 females) and 75 (cohort NORA75, 143 males and 180 females). METHODS: Body composition was measured with BIA (BIA-101, RJL system, Detroit) in both cohorts and was estimated by a four-compartment (4C) model from total body water (TBW) and total body potassium (TBK) in a sub-sample of the NORA75 cohort. The FFM(BIA) was validated against the FFM from the 4C model (FFM(4C)). RESULTS: The FFM(BIA) correlated well with FFM(4C) (r=0.95, SEE=2.64 kg). The FFM(BIA) (kg) in 70-y-old males and females were 58.5+/-5.4 and 43.4+/-4.4, and for 75-y-old males and females were 56.1+/-4.7 and 42.5+/-4, respectively. The body fat in kg (FM) among 70-y-old males and females were 25.2+/-8.1 and 25.7+/-8.4, and for 75-y-old males and females were 21.7+/-7.1 and 22.8+7.2, respectively. The percent body fat (BF%) among 70-y-old males and females were 29.5+/-5.8 and 36.3+/-6.4, and for 75-y-old males and females were 27.3+/-6 and 34.1+/-6.1, respectively. CONCLUSION: The FFM, FM and BF% from this study might be used as reference values for Swedish elderly aged 70 and 75 y.     

Estimating geriatric patient's body weight using the knee height caliper and mid-arm circumference in Hong Kong Chinese

The use of the knee height caliper is a convenient way to estimate a patient's body weight. However, the equation devised to estimate an individual's body weight was specifically designed for Caucasians and Blacks. Therefore, this study is to assess the suitability of the knee height caliper among Chinese geriatric patients residing in Hong Kong. Over a six-month period, all geriatric patients from an acute care hospital and private nursing home in the Kwun Tong were recruited into the study. Only patients/residents that were considered unstable with ascites; low blood pressure; on cardiac monitors or had respiratory difficulties were excluded. Measurements from the knee height caliper and mid-arm muscle circumference of the patients were necessary for estimating their body weights. The actual body weights measured with calibrated bed, chair or portable scales was compared with the calculated body weights from the equation. A comparison of the mean and linear regression was performed for analysis of the results. A total of 300 geriatric patients (200 females and 100 males) were recruited. The mean MAC and knee height results were as follows: 25.1 cm (SD 3.9) for females and 26.2 cm (SD 3.2) for males; and 45.75 cm (SD 2.09) for females and 48.98 cm (SD 2.09) for males respectively. The mean difference among the male group was 0.4222 (95% CI: -0.54, 1.39) with a mean estimated body weight of 58.1 kg (SD 10.1) and a mean actual body weight of 57.7 kg (SD 9.9). The mean difference among the female group was 2.9649 (95% CI: 2.30, 3.63) with a mean estimated body weight of 51.6 kg (SD 10.9) and a mean actual body weight of 48.6 kg (SD 10.1). A new equation devised from the data is as follows: Chinese males (over 60 years of age) (R-square -0.81) Weight = [knee height (cm) x 0.928 + mid-arm circumference (cm) x 2.508 - age (years) x 0.144] - 42.543 +/-9.9kg of actual weight for 95% of Chinese males; Chinese females (over 60 years of age) (R-square - 0.82) Weight (kg) = [knee height (cm) x 0.826 + mid-arm circumference (cm) x 2.116 - age (years) x 0.133] - 31.486 +/-10.1kg of actual weight for 95% of Chinese females. The results showed that the mean estimated body weight calculated from the knee height equation (for Caucasians) was significantly larger than the mean actual body weight for the Chinese subjects. This study suggests that the knee height caliper is a useful tool for estimating the body weights. However, a multi-center study is necessary to validate the new equation for the elderly Chinese population.     

Change of body composition over an eight year period among Japanese university students

This study examined the change of body composition in Japanese university students. Subjects were university students divided into two groups by sex for two different time periods: 67 males and 46 females for 1986-1987 and 47 males and 64 females for 1994-1995. Body height, weight, and underwater weight were measured to estimate the percentage of body fat. The fat mass index (FMI) was applied after adjusting fat mass and the fat-free mass index (FFMI) applied after adjusting fat-free mass for body physique by dividing (body height)2. The mean body mass index (BMI) increased from 1986-1987 to 1994-1995 in males and decreased in females, although there were no statistical differences between two time periods in both sexes. The FMI indicates that in 1994-1995 males had significantly more fat adjusted for body height than in 1987. Females in 1994-1995 had significantly less FFMI than those in 1986 despite FMI similar to that of 1986. Our results thus warn against a trend toward excessive thinness in collegiate females and insufficiency of evaluating body composition using the BMI alone.     

The validity of predicted body fat percentage from body mass index and from impedance in samples of five European populations

OBJECTIVES: To test and compare the validity of a body mass index (BMI)-based prediction equation and an impedance-based prediction equation for body fat percentage among various European population groups. DESIGN: Cross-sectional observational study. SETTINGS: The study was performed in five different European centres: Maastricht and Wageningen (The Netherlands), Milan and Rome (Italy) and Tampere (Finland), where body composition studies are routinely performed. SUBJECTS: A total of 234 females and 182 males, aged 18-70 y, BMI 17.0-41.9 kg/m(2). METHODS: The reference method for body fat percentage (BF%(REF)) was either dual-energy X-ray absorptiometry (DXA) or densitometry (underwater weighing). Body fat percentage (BF%) was also predicted from BMI, age and sex (BF%(BMI)) or with a hand-held impedance analyser that uses in addition to arm impedance weight, height, age and sex as predictors (BF%(IMP)). RESULTS: The overall mean (+/-s.e.) bias (measured minus predicted) for BF%(BMI) was 0.2+/-0.3 (NS) and-0.7+/-0.3 (NS) in females and males, respectively. The bias of BF%(IMP) was 0.2+/-0.2 (NS) and 1.0+/-0.4 (P<0.01) for females and males, respectively. There were significant differences in biases among the centres. The biases were correlated with level of BF% and with age. After correction for differences in age and BF% between the centres the bias of BF%(BMI) was not significantly different from zero in each centre and was not different among the centres anymore. The bias of BF%(IMP) decreased after correction and was significant from zero and significant from the other centres only in males from Tampere. Generally, individual biases can be high, leading to a considerable misclassification of obesity. The individual misclassification was generally higher with the BMI-based prediction. CONCLUSIONS: The prediction formulas give generally good estimates of BF% on a group level in the five population samples, except for the males from Tampere. More comparative studies should be conducted to get better insight in the generalisation of prediction methods and formulas. Individual results and classifications have to be interpreted with caution.     

A new predictive equation for resting energy expenditure in healthy individuals

A predictive equation for resting energy expenditure (REE) was derived from data from 498 healthy subjects, including females (n = 247) and males (n = 251), aged 19-78 y (45 +/- 14 y, mean +/- SD). Normal-weight (n = 264) and obese (n = 234) individuals were studied and REE was measured by indirect calorimetry. Multiple-regression analyses were employed to drive relationships between REE and weight, height, and age for both men and women (R2 = 0.71): REE = 9.99 x weight + 6.25 x height - 4.92 x age + 166 x sex (males, 1; females, 0) - 161. Simplification of this formula and separation by sex did not affect its predictive value: REE (males) = 10 x weight (kg) + 6.25 x height (cm) - 5 x age (y) + 5; REE (females) = 10 x weight (kg) + 6.25 x height (cm) - 5 x age (y) - 161. The inclusion of relative body weight and body-weight distribution did not significantly improve the predictive value of these equations. The Harris-Benedict Equations derived in 1919 overestimated measured REE by 5% (p less than 0.01). Fat-free mass (FFM) was the best single predictor of REE (R2 = 0.64): REE = 19.7 x FFM + 413. Weight also was closely correlated with REE (R2 = 0.56): REE = 15.1 x weight + 371.     

Stature of early Europeans

The ancestors of modern Europeans arrived in Europe at least 40,000 years before present. Pre-glacial maximum Upper Palaeolithic males (before 16,000 BC) were tall and slim (mean height 179 cm, estimated average body weight 67 kg), while the females were comparably small and robust (mean height 158 cm, estimated average body weight 54 kg). Late Upper Palaeolithic males (8000-6600 BC) were of medium stature and robusticity (mean height 166 cm, estimated average body weight 62 kg). Stature further decreased to below 165 cm with estimated average body weight of 64 kg in Neolithic males of the Linear Band Pottery Culture, and to 150 cm with estimated average body weight of 49 kg in Neolithic females. The body stature of European males remained within the range of 165 to 170 cm up to the end of the 19th century.     

Mean body weight, height, and body mass index, United States 1960-2002

This report presents trends in national estimates of mean weight, height, and body mass index (BMI) from the National Health Examination and the National Health and Nutrition Examination Surveys between 1960 and 2002. The tables included in this report present data for adults by sex, race/ethnicity, and age group and for children by sex and year of age. Mean weight and BMI have increased for both sexes, all race/ethnic groups, and all ages. Among adults, mean weight increased more than 24 pounds. Although not as dramatically, mean height has also increased for most ages and for both males and females.     

Body mass index, overweight and obesity among Kuwaiti intermediate school adolescents aged 10-14 years

OBJECTIVES: The purpose of this cross-sectional study was to assess the levels of overweight and obesity among Kuwaiti intermediate school adolescents aged 10-14 y. The study comprised a multistage stratified random sample of 14659 adolescents (7205 males and 7454 females), which constitutes approximately 17% of the target population of this school level. METHODS: Weights and heights of the adolescents were measured, from which the body mass index (BMI), which is the weight in kilograms divided by the height in meters squared (kg/m2), was calculated. Overweight and obesity were defined as BMI >85th and >95th centiles, respectively, of the National Center for Health Statistics (NCHS) reference data. RESULTS: The overall prevalence of overweight and obesity among males were 30.0 and 14.7%, respectively (P<0.001). The overall prevalence of overweight and obesity among females were 31.8 and 13.1%, respectively (P<0.001 and P<0.01). There was no consistent rise or decline in overweight and obesity in both genders with respect to age. However, the overall prevalence of overweight was lower in males than in females but obesity was higher in males than in females. CONCLUSION: When compared to the NCHS reference population, the BMI of Kuwaiti adolescents exceeded that of the Americans in each centile category > or = 50th centile. Health education programmes should be instituted to control this syndrome in order to prevent future risk of obesity-related diseases.     

Body composition in the elderly: Total body water and anthropometry

Body composition measured with isotopic dilution was compared with anthropometric measurements. The study was carried out in 47 subjects from both sexes, 65 to 92 years old. Total body water (TBW), anthropometric measurements, and dynamometry were assessed. TBW was significatively higher in men than women and decreased with age. Dynamometry and fatfree mass were well correlated (r=0.73 in males and r=0.58 in females) and significantly different between sexes. A negative correlation was found for dynamometry with age, being significant for women. Linear regression equations to predict TBW from anthropometric measurements in males and females were obtained: Males: TBW(I)=19.349+0.617 weight(kg) — 0.931 mid-arm circumference(cm)+0.122 dynamometry (kg) Females: TBW(l)=−5.531+0.343 weight(kg)-0.213 triceps skinfold (mm)+ 0.148 dynamometry(kg) + 3.424 wrist diameter (cm). This simple model is proposed for use in epidemiological and field studies where other more sophisticated methods can not be applied.     

Using obese-specific charts of height and height velocity for assessment of growth in obese children and adolescents during weight excess reduction

OBJECTIVE: The influence of weight excess reduction on height and height velocity of obese subjects should be evaluated on the basis of appropriate standards, since the pattern of growth of obese subjects is different from that of normal weight subjects. DESIGN, SUBJECTS AND MEASUREMENTS: Height, weight and triceps skinfold thickness were recorded from 17987 school subjects (9256 males and 8731 females), 3-18 y of age, from three provinces of central Italy, and a growth reference curve of height was constructed. Using BMI (as computed using the tables of Rolland-Cachera et al) and triceps skinfold thickness, normal-weight subjects (NWS) and obese subjects (OS) were identified and specific reference curves (mean+/-s.d. every sixth month of age) were developed for both groups. Centiles of height were also calculated for OS. Various (2-4) measurements of height in school subjects were performed and a graph of height velocity (HV) was constructed in NWS and in OS using the JPPS method. The yearly mean +/-s.d. of HV was also calculated, based on square root transformed data (in order to realise a Gaussian distribution), deriving from successive measurements in total subjects, in NWS and in OS. The z-scores of height and of the square root of HV were calculated in 217 obese subjects (125 males and 92 females) before and during a weight excess reduction programme (WERP). Obese subjects in WERP who showed a reduction of z-score of BMI were considered as 'responsive'; those who either maintained or showed an increase of z-score of BMI were considered as 'non-responsive'. Obese subjects in WERP were followed for 1-4 y, giving the following results: 0-1 y, 142 responsives and 75 non-responsives; 0-2 y, 76 responsives and 33 non-responsives; 0-3 y, 35 responsives and 30 non-responsives; 0-4 y, 24 responsives and 18 non-responsives. RESULTS: Compared to NWS, OS showed a significantly greater HV in 4-9y males and in 4-8y females, but in older children the pubertal spurt was reduced and more precocious. As a result, the height of OS, which was greater in 3-13 year-old males and in 3-11.5 year-old females, subsequently showed a reduction, as compared to that of NWS, in 16-18 year-old males and in 13-18 year-old females. In both responsive and non-responsive groups of obese subjects in WERP, the z-scores of height showed a reduction during WERP when evaluated using the reference curve of the total school population. In contrast, when their growth was evaluated according to the obese-specific reference curve, no significant variation was observed comparing both z-scores before and during the WERP. CONCLUSIONS: More appropriate information on the growth of obese subjects may be obtained when evaluating the height and HV according to obese-specific reference standards from the same population of origin. Adopting this modality, no significant variation of height resulted during WERP in obese children.     

Age-appropriate body mass index in children with achondroplasia: interpretation in relation to indexes of height

BACKGROUND: Achondroplasia is the most common short stature skeletal dysplasia, with an estimated worldwide prevalence of 250 000. Body mass index (BMI)-for-age references are required for weight management guidance for children with achondroplasia, whose body proportions are unlike those of the average stature population. OBJECTIVE: This study used weight and height data in a clinical setting to derive smoothed BMI-for-age percentile curves for children with achondroplasia and explored the relation of BMI with its components, weight and height. DESIGN: This was a longitudinal observational study of anthropometric measures of children with achondroplasia from birth through 16 y of age. RESULTS: The analysis included 1807 BMI data points from 280 children (155 boys, 125 girls) with achondroplasia. As compared with the BMI of peers of average stature, the BMI in children with achondroplasia is higher at birth, lacks a steep increase in infancy and a later nadir between 1 and 2 y of age, and remains substantially higher through 16 y of age in both sexes. Patterns of change in height and weight in children with achondroplasia are unique in that there is no overlap in the height distribution after 6 mo of age and no spike in height velocity during infancy or puberty-the 2 periods of greatest linear growth in individuals of average stature. CONCLUSIONS: Sex- and age-specific BMI curves are available for children with achondroplasia (birth to 16 y of age) for health surveillance and future research to determine associations with health outcomes (eg, cardiovascular disease, diabetes, and indication for and outcome of surgery).     

Height reduction, determined using knee height measurement as a risk factor or predictive sign for osteoporosis in elderly women

OBJECTIVE: We assessed the value of height reduction, calculated using knee height measurement, as a risk factor or predictive sign for osteoporosis in healthy elderly women. METHODS: In 181 healthy women 76 +/- 5 y of age, height, weight, and knee height were evaluated. Femoral and spine bone mineral densities and body compositions were measured using dual-energy X-ray absorptiometry. In 76 young women 27 +/- 4 y of age, a regression equation to predict height, based on knee height, was derived. Using this equation, maximum attained height and height loss were calculated in elderly women, which was correlated to bone mineral density. RESULTS: The equation to predict height was height (cm) = knee height (cm) x 2.22 + 50.54. The calculated height loss in elderly women was -6.1 +/- 3.8 cm or -0.08 +/- 0.05 cm/y of age. Height loss and hip circumference were significant predictors of spine bone mineral density. In the case of femoral bone mineral density, to the same predictors, a negative effect of waist circumference was added. Women in the highest quintile of height reduction (>0.199 cm/y) had an odds ratio of 4.5 (95% confidence interval 1.56-13.3, P < 0.02) for femoral osteoporosis. CONCLUSION: Knee height can be used as an accurate measurement of height loss in the elderly, which is a significant predictor of femur and spine bone mineral densities, in addition to hip circumference.