Indices of relative weight and obesity

The role of nutritional status, airway obstruction, hypoxia, and abnormalities in serum lipid composition in limiting exercise tolerance in children with cystic fibrosis

Previous work has shown that impaired exercise tolerance in children with cystic fibrosis (C.F.) is related to the severity of airway obstruction without elucidating the possible roles of hypoxia or malnutrition. It has been suggested that poor nutrition leads to abnormalities in serum fatty acids composition, which may lead to tissue hypoxia. We investigated the roles of hypoxia, pulmonary mechanics, nutritional status, and serum fatty acid composition in limiting exercise tolerance in C.F. In 20 children with C.F., exercise tolerance, while breathing air and while breathing oxygen, was evaluated on a cycle ergometer and compared to pulmonary function tests, anthropometric data, serum lipid compostition, and clinical condition. The mean percent work expected from height (Wmax) was 75, and was unchanged by O2. Wmax correlated significantly with the degree of respiratory impairement, the discrepancy between height and weight, and the clinical score but not serum fatty acid composition. Where measured, no child at any time had an elevated end tidal CO2(PetCO2). We conclude that nutritional status and airway obstruction are closely correlated with exercise tolerance in C.F. and that, unlike the case in adults with chronic obstructive pulmonary disease, exercise-limiting dyspnea occurs in the presence of a normal PetCO2.

Muscle strength and body composition as determinants of blood pressure in young men

The correlations of blood pressure to various indices of muscularity and fatness were studied in 183 young healthy men (mean age 19.7, SD 2.1 years). Systolic pressure showed significant positive correlations with body fat percentage, isometric strength of trunk extensors, body mass index, lean body mass, strength of leg extensors, heart rate, and the sum of four skinfolds. Diastolic pressure had significant positive correlations with body mass index, lean body mass, body fat percentage, sum of skinfolds, strength of leg extensors, strength of trunk extensors, and age. A stepwise selective multiple regression analysis for systolic pressure resulted in four significantly correlating variables: body fat percentage (p less than 0.001), heart rate (p less than 0.01), lean body mass (p less than 0.05), and strength of trunk extensors per kg body weight (p less than 0.05). For diastolic pressure the analysis resulted in two explaining variables: body mass index (p less than 0.001) and age (p less than 0.05). In a regression equation with 13 variables the strength of trunk flexors was negatively correlated with diastolic pressure. It is concluded that both fatness and muscularity are factors related to blood pressure in young men. The muscularity effect is more clearly associated with trunk and leg extensor strength.

Obesity in schoolchildren and their parents

The height, weight and left triceps skinfold thickness of 2190 schoolchildren were measured and the heights and weights of their parents obtained from a postal questionnaire. Power-type obesity indices were used to correct weight for height in parents and children. Preliminary analysis of the distribution of obesity using arbitrarily chosen cut-off points to define the obese, normal and lean parent indicated the presence of a group of 'super-obese' families. The spline technique was used to analyse these data as continuous variables, and showed that the 'super-obese' group of families was too small to be of any practical importance. The relationship between obesity in parents and their children has also been investigated using the spline regression technique. The results show that the relationship is linear but that only 6% of the total variation of observed obesity in children is attributable to variation in the parents' reported obesity. However, a structural analysis indicates a direct relationship between obesity of parents and children. This is obscured in the regression analysis by the large within-subject variability of observed obesity in both parents and children.

The effect of westernization on native populations. Studies on a Micronesian community with a high diabetes prevalence

A diabetes prevalence study in 1975 on an isolated urbanized Central Pacific island (Nauru) showed rates comparable to the American Pima Indians--the highest yet recorded in the world literature. This paper reports the results of a follow-up study and the high prevalence has been confirmed. In this survey of 417 people aged ten years and over, 9.8% were known diabetics. With a plasma glucose of 160 mg/100 ml or over at two hours after a 75 gram oral glucose load as the criterion of diagnosis, , diabetes was detected in a further 19.2%, making a total diabetic population of 29% in the population studied. The prevalence of diabetes was 44% in people aged 20 years and over. A further 7% had borderline diabetes on the basis of a two-hour plasma glucose of 140--159 mg/100 ml. Parity did not appear to be a causative factor in relation to the high diabetes prevalence. However, obesity is common in this community and is more marked than that seen in other Pacific or Caucasian communities. The high prevalence of diabetes in this population appears to be related to the inter-action of environmental factors, such as obesity, with a diabetic genotype. The results confirm the possible detrimental effects of westernization on native populations.

Breast cancer incidence according to weight and height in two cities of the Netherlands and in Aichi prefecture, Japan

A study was made in the cities of Rotterdam and The Hague, the Netherlands, and in Aichi prefecture, Japan, to assess the effect of weight and height (and their combinations) on the age-specific incidence of breast cancer. It is based on a comparison between 1006 cases of breast cancer and 4201 women from the general population, 33-69 years old. The results suggest that about one-half of the differences in incidence between the regions in Holland and Japan can be attributed to differences in body weight and height. In breast cancer patients in Rotterdam and The Hague those with metastases in axillary involvement. A hormonal factor related to body weight and/or height might be responsible for the increased incidence and the more rapid course of breast cancer in women with a large body mass.

A comparison of the skinfold method with extent of 'overweight' and various weight-height relationships in the assessment of obesity

1. Body-weight, height, skinfold thickness and body density measurements were made on 245 men and 324 women aged between 17 and 72 years. The body fat content of each individual was calculated from his density measurement using equations similar to that of Siri (1956) but appropriate to age, muscular development, and extent of obesity. Regression equations were then derived for separate age-groups for the prediction of body fat from (1) weight–height (W–H) relationships (W:H, W:H2 W:H3, W0.33:H, H:W0.33), (2) ‘percentage overweight’ (body-weight:mean body-weight; W:W;) and ‘percentage desirable weight’ body-weight: ‘desirable weight’ (mean weights for men and women aged 20-24 years); (W:DES), (3) the independent variables weight and height incorporated in a regression equation, (4) skinfold measurements.

2. The correlations between height and indices, W:H, W:H3, W0.33:H and H:W0.33: were substantially different from those between height and body fat estimated by densitometry.

3. The method having the highest correlation with body fat estimated by densitometry was the skinfold method, although in the older groups of women other methods sometimes gave equally good correlations. The index H:W0.33 had a negative correlation with body fat, and the indices W:H, W0.33:H and W:H3 had a lower correlation with body fat estimated by densitometry than did the other indices. These indices are therefore unsuitable measures of obesity, and this is in agreement with the findings of other workers.

4. The correlations betweeen body fat estimated by densitometry and the indices W:H2, W:W, W:DES and the equations incorporating the independent variable weight and height are all very similar, although it is not appropriate to use the index W:W; as a measure of obesity in groups of people of widely different ages.

5. The standard error of prediction of body fat from skinfold measurement may be of the same order of magnitude as the standard error of prediction of body fat by densitometry. It is therefore probably inappropriate to assess the accuracy of the skinfold method by comparison with the density method alone.

6. From the distribution patterns obtained, it was evident that compared with the density method, all methods tended to over-estimate body fat in very lean individuals. The skinfold method however showed this tendency to only a relatively small extent.

Current controversies in childhood obesity

The conclusions that one can state with assurance are remarkably few. Adiposity in children is best monitored clinically by the measurement of skin-fold thickness. The likelihood that obesity will progress from infancy to childhood to adult life is still questionable and may be more important in the individual child than as a significant cause of adult obesity. Behavioral and social factors pedominate in etiology, yet biologic factors, including genetic, are also involved. Behavioral and social factors are critical in the significance of obesity to the individual. Although there are definite disease hazards, they appear to be predominantly confined to the very obese. The best treatment appears to be prophylaxis, again heavily involving behavioral and social factors as well as the wide-spread distribution of sound nutritional information. When prophylaxis fails, the behavioral modification approach to therapy currently holds the greatest promise.

Relation of body weight to development of ischemic heart disease in a cohort of young North American men after a 26 year observation period: the Manitoba Study

The role of overweight as a risk factor for ischemic heart disease remains controversial. Therefore, in the Manitoba Study of a cohort of 3,983 men with a mean age at entry of 30.8 years, initial measurements of body weight, represented by body mass index (weight/height2), were compared with the 26 year incidence of ischemic heart disease. After adjustment for the effects of age and blood pressure in univariate and multivariate analysis, body mass index was a significant predictor of the 390 cases of ischemic heart disease. To elucidate this relation further, the cohort was further analyzed after categorization by age at entry, time of occurrence of disease after entry and manifestation of ischemic heart disease. The association with weight was most apparent in men less than 40 years of age and was not evident until 16 years of follow-up. A high body mass index was significantly associated with development of myocardial infarction, sudden death and coronary insufficiency or suspected myocardial infarction; the relation was strongest with sudden death. Among men who had a myocardial infarction, body mass index was more strongly associated with sudden death and was the best predictor of myocardial infarction occurring after 20 years of observation. Thus, after adjustment for the effect of age and blood pressure, overweight is a definite risk factor but primarily in younger men, after long periods of observation and for certain manifestations of ischemic heart disease.

Blood pressure in tenth-grade students: results from the Chicago Heart Association Pediatric Heart Screening Project

This report is based on 13,231 tenth-grade students who participated in the Chicago Heart Association Pediatric Heart Screening Project. The blood pressures of these fifteen and sixteen-year-olds were analyzed with respect to sex, race, adiposity, pulse rate, and father's educational attainment. The mean systolic blood pressure was higher in boys than girls by nearly 5 mm Hg, but mean diastolic blood pressure was lower by less than 1 mm Hg. Black tenth-graders had higher mean diastolic blood pressure than whites; the difference in systolic blood pressure was not statistically significant. Adiposity and resting pulse rate were positively correlated with systolic blood pressure and, to a lesser degree, with diastolic blood pressure. After taking adiposity and pulse rate into account, father's educational attainment had a small but statistically significant negative association with diastolic blood pressure in white but not in black students. Nearly 5 percent of students were recalled for a second test because the initial screening blood pressures equaled or exceeded 150 mm Hg systolic or 90 mm Hg diastolic, and almost half of students at the recall examination continued to have pressures of 145/85 or greater.

Body fat: its relationship to coronary heart disease, blood pressure, lipids and other risk factors measured in a large male population

Obesity is variably considered to be a major contributor to hypertension and hyperlipidemia, and its treatment is recommended in the management of coronary heart disease. Total body fat was measured by tritium dilution in a large male population and its relationship to age, blood pressure, serum lipids, uric acid and the diagnoses of coronary heart disease, hypertension and glucose intolerance was examined. In addition, three commonly used weight: height indices of obesity were correlated with each of these parameters. The correlation of body fat with blood pressure, serum cholesterol and triglycerides, although statistically significant, was of only small magnitude. Mean levels of body fat were not significantly different between patients with coronary disease and control subjects, whereas serum cholesterol and, to a lesser extent, systolic blood pressure were potent risk factors for the disease. It is concluded that obesity is only a minor determinant of blood pressure and lipid level, and that its contribution to coronary heart disease is small or nonexistent.

Childhood antecedents of adult obesity. Do chubby infants become obese adults?

We investigated whether obese infants tend to become obese adults. Records of subjects born between 1945 and 1955 were reviewed to select three cohorts based on weight in the first six months of age, which exceeded the 90th percentile at least once, ranged between 25th and 75th percentiles or was below 10th percentile at least once. Three hundred and sixty-six subjects, now between 20 and 30 years of age, were located and their present height and weight determined. Thirty-six per cent of those exceeding the 90th percentile as infants were overweight adults, as compared to 14 per cent of the average age and light-weight infants. A significant increase (chi square = 17.2, p less than 0.001) in adult obesity was evident when the infant exceeded the 75th percentile that was independent of his height. Social class, educational level, and parental weight all correlated with adult weight (p less than 0.001). Sex and ordinal position of birth did not. The data suggest that infant weight correlates strongly with adult weight independently of other factors considered.

The influence of premedication, anaesthesia, age and weight on glucose uptake into human isolated skeletal muscle

The effect of the anaesthetic procedures and of the sex, age and weight of each patient on glucose uptake and glycogen content of human skeletal muscle has been studied in vitro in the presence and absence of insulin. Statistical analysis indicated that the relationships between age and both glucose uptake and the response to insulin were significant, older patients in general having higher uptakes. The blucose uptake was highly correlated with the three obesity indices (ponderal index, body mass index and percentage of the ideal weight). The anaesthetic agents had no significant effect on glucose uptake. The choice of premedication appeared to have a small effect on the basal glucose uptake level, but as the choice of premedication was also age related and age itself was a significant factor, this effect may not be of importance. It is concluded that the age and the degree of obesity of the patients ought to be taken into account when studying samples of human muscle.

Follow-up study of patients treated by X-ray epilation for Tinea capitis; resurvey of post-treatment illness and mortality experience

This is the second follow-up study of 2,215 persons who during childhood between 1940 and 1959 had been given x-ray therapy for tinea capitis and of 1,395 persons well matched for age, sex, and race who were treated for the same disease during the same period without the use of x-ray therapy. The major finding of the study was an excess incidence in the irradiated cases of tumors of the head and neck including the skin, brain, thyroid, and parotid. However, between the groups there was no difference in death due to malignant neoplasms or any other cause. Among white patients, a 40% excess of treated psychiatric disorders was observed in the irradiated group, but there was no difference among blacks.

Do American born Japanese children still grow faster than native Japanese?

Growth patterns of Japanese schoolchildren in Hawaii, composed of 2,954 boys and 3,213 girls aged between 11 and 17, were compared with those comparable groups of Japanese schoolchildren in Japan based on the data published by the Japanese Ministry of Education. Growth characteristics studied were height, weight, and relative weight index, weight/(height). The Hawaii-Japanese boys were taller at early ages but the difference disappeared by age 16. Native Japanese girls were shorter than Hawaii-Japanese until age 13, but they overtook the latter by age 14, exceeding them in height after age 15. A similar pattern was found in weights of girls but the Hawaii-Japanese boys remained consistently heavier by 5.0 to 9.0 kg than native Japanese. The relative weight measure indicated that the Hawaii boys were more "obese" than native Japanese boys for the growth period studied; whereas the same tendency was maintained until age 15 in girls. These observations indicate a marked degree of convergence of the patterns of physical growth of the two populations, whose differences were unmistakably in favor of American born children in earlier studies. It is concluded that the convergence is due largely to the improved environmental conditions in Japan in recent years.

Pathophysiologic observations in prehospital ventricular fibrillation and sudden cardiac death

In order to better understand the problem of prehospital sudden cardiac death (SCD) two groups of individuals were studied. One group was monitored by rescue squads during attempted rescue. These subjects were defibrillated from prehospital ventricular fibrillation (VF) and hospitalized if they survived or autopsied if they could not be resuscitated. The second group were SCDs which were witnessed and described by observers. Detailed past histories of both groups were collected, and either clinical or autopsy diagnoses were obtained.

On the day of death or VF, one quarter reported new symptoms (primarily chest pain and dyspnea) preceding collapse by more than 30 minutes, one quarter reported symptoms lasting from 1 to 30 minutes, and one half collapsed instantaneously or within 1 minute of acute symptoms. A history of old myocardial infarction (MI) was present in 41% and of angina pectoris in 54%, and 27% reported new or changing symptoms within four weeks.

In defibrillated survivors, "would-be SCDs," electrocardiographic (ECG) changes of acute myocardial infarction (AMI) or ischemia were nearly three times more frequent than changes detected histologically in SCDs, and in the former involved predominantly the anterior wall in contrast to the inferior wall in most autopsied deaths. This disparity implicates acute myocardial lesions, particularly of the anterior wall, in the majority of SCDs.

Acute coronary lesions were found in 58% of SCDs autopsied. Most of these were ruptured plaques although almost one fifth of all autopsied SCDs had thromboses without intimal rupture. Severe chronic multivessel stenosis was present in most subjects, although 15% had only disease of a single vessel and in these, the left anterior descending (LAD) or left main coronary artery were involved in three quarters.

The SCD population may be subgrouped into those with recent MI, those with only myocardial ischemia, and those with no detectable myocardial change. When rescuers were able to monitor prehospital SCDs, VF was found in the majority; however, 28% did have other terminal rhythms.

Diurnal variation in glucose tolerance: associated changes in plasma insulin, growth hormone, and non-esterified fatty acids

Oral glucose tolerance tests were performed in the morning and afternoon of separate days on 31 people derived from a normal population sample. Blood sugar levels were higher in the afternoon test from and including 60 minutes after the glucose load. The degree of diurnal variation was similar in men and women, but greater in the older half of the group. It was negatively correlated with the degree of obesity. The plasma insulin response was less at the 30 minute time point in the afternoon, but significantly exceeded the morning values at 120 and 150 minutes after the glucose load. Growth hormone levels were similar in morning and afternoon tests. Fasting non-esterified fatty acid levels were significantly higher before the afternoon test.The relatively impaired glucose tolerance in the afternoon is associated with a delayed insulin response to the glucose load. This seems unlikely to be the sole explanation, however, and increased non-esterified fatty acid metabolism with a consequent decrease in glucose disposal may also contribute.

Coronary artery disease in 116 kindred with familial type II hyperlipoproteinemia

Analysis of cardiovascular status in adult relatives of 116 kindred affected with familial hyperbetalipoproteinemia (type II hyperlipoproteinemia) was carried out to assess coronary artery disease (CAD) risk in relatives with type II (II) compared to unaffected family members. Over 90% of the 738 living relatives were interviewed by one investigator and 12 lead electrocardiograms were obtained. In these, and in 285 deceased relatives, physician and hospital records were utilized to determine CAD events by standard criteria. This study, the largest of its kind, permitted more precise and extensive determination of the CAD risk accompanying severe hyperbetalipoproteinemia than has heretofore been possible. CAD was diagnosed in 29.5% of II's compared with 10.5% of normal relatives (N) ( P < .001). The II's and N's did not differ significantly with regard to age distribution, sex, hypertension, smoking habits, or body mass index. According to the Rose questionnaire, angina pectoris was diagnosed in 21.8% of II's and 6.5% of N's ( P < .001). Documented myocardial infarction occurred in 6% of II's versus 1% of N's ( P = .002). CAD death or myocardial infarction occurred in 10.1% of II's compared with 1.8% of N's ( P < .001). The cumulative probability of nonfatal or fatal CAD by age 40 in male II's was 16% (1 in 6); by age 60, the expectation of an event had risen to 52% (1 in 2). Among male N's, the risk of nonfatal or fatal CAD by age 60 was 12.7%, lagging 20 years behind that seen in male II's. In female II's, the risk of nonfatal or fatal CAD by age 60 was 32.8% compared with only 9.1% in female N's.