ISSN:1042-0533    

DOI:10.1002/ajhb.1310060102

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

年代:1994

数据来源: WILEY

摘要:

AbstractStanley Garn's book,Human Races(1965), captured the essence of the new genetic concept of ethnic groups as populations which share the same gene pool, shaped by natural selection. Since then new genetic traits, especially DNA polymorphisms, have been employed to build upon his vision. They have proven useful in the forensic sciences, medicine, and the human biology of adaptation, migration, evolution, and phylogeny. Some diseases like sickle cell anemia are controlled by single genes concentrated in a large ethnic group; their alleles are valuable for understanding human biology. Other conditions with a marked genetic component, such as diabetes, heart disease, and osteoporosis, predominate in certain ethnic groups. The new molecular biology tends to support the migration of farmers from west Asia into Europe in the Neolithic, the isolation of the Basques, and the early entrance of people into the New World. Some DNA data also favor the debatable hypothesis of the development of humanity in Africa and its subsequent dispersal. In many cases linguistic distance parallels genetic distance as language tends to influence gene flow. Apolipoproteins, with alleles unique to one major population group, are useful markers of admixture as well as significant for cardiovascular health. The Gullah‐speaking Black people of coastal Carolina are distinctive and close to African ancestors in language, culture, and biology, including genetic markers. Modern research confirms that race (by any name) is quantitative rather than qualitative, relative rather than absolute, and dynamic rather than static. © 1994 Wiley‐Liss,

ISSN:1042-0533    

DOI:10.1002/ajhb.1310060103

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

年代:1994

数据来源: WILEY

摘要:

AbstractOver a period of 28 years, a succession of cross‐sectional surveys was carried out on young women entering the University College of Swansea (1959–1970) and then the University of Warwick (1971–1986) each year. Recall data on age at menarche and measurements of stature provide an indication of secular trends in growth and maturation in this section of the population of Britain. The earlier trend to younger age at menarche came to an end in girls born in approximately 1946 and entering university in 1964, and subsequently reversed, so that there is now a secular increase in menarcheal age. The successive analyses of stature show no such reversal, but instead a steady increase in mean stature throughout the period. © 1994 Wiley‐L

ISSN:1042-0533    

DOI:10.1002/ajhb.1310060104

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

年代:1994

数据来源: WILEY

摘要:

AbstractSkeletal maturia (Tanner‐Whitehouse II [TW II]), growth status, and motor fitness were compared in boys having high and low trunk/extremity skinfold ratios (T/E ratio). The T/E ratio was based on the sums of the subscapular and midaxillary, and the triceps and medial calf skinfolds. The sample included 80 boys, age 8 through 11 years, who represented the highest and lowest quartiles of the distribution of the T/E ratio (10 boys per quartile in each age group). Chronological and skeletal ages did not differ between boys in the highest and lowest quartiles, with the exception of the 10‐year‐old sample in the highest quartile, in whom skeletal age was significantly advanced. Boys in the highest quartile tended to be slightly taller, but especially heavier and fatter (sum of four skinfolds). They thus had a higher body mass index (BMI), which was elevated in part due to increased muscle mass as reflected in a larger estimated midarm muscle circumference. In contrast, boys in the lowest quartile tended to perform better, both absolutely and per unit body mass, in the three motor tests (run, jump, throw), while there were no consistent differences in absolute strength. However, boys in the lowest quartile tended to be stronger and to perform better per unit body mass. The results thus suggest that more centrally distributed subcutaneous fat may have a negative effect on the motor fitness of children, and this effect is mediated in part through excess fatness. © 1994 Wiley‐L

ISSN:1042-0533    

DOI:10.1002/ajhb.1310060105

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

年代:1994

数据来源: WILEY

摘要:

AbstractTo determine the effects of changes in maternal cigarette use during pregnancy on birthweight, a sample of Caucasian births free of major malformations (n = 9,943) was examined. Births were stratified by level of maternal smoking in the first trimester and subdivided according to whether the mother continued at the same level, reduced, or quit by the second trimester. Birthweights were adjusted statistically for extraneous variables. As expected, second and third trimester cigarette use was associated with birthweight, but so too was cigarette use during the first trimester, and the effect of quitting varied significantly with the level of first trimester smoking. Among moderate and light smokers, who comprise the majority of smokers, quitting before the second trimester is associated with heavier infants. However, infants of heavy smokers who quit by the second trimester did not weigh significantly more than infants of mothers who continued to smoke heavily throughout pregnancy, and weighed significantly less than infants of nonsmokers or other smokers who quit. Thus, quitting by the end of the first trimester may not completely negate the effect of heavy first trimester smoking, and the adaptive value of qutting is unequal among different levels of first trimester smoking. Further research on prenatal growth should take cigarette smoking in all trimesters into account. © 1994 Wiley‐Liss, I

ISSN:1042-0533    

DOI:10.1002/ajhb.1310060106

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

年代:1994

数据来源: WILEY

摘要:

AbstractA summary of the work performed by Stanley Garn relating to muscle mass while he worked at the Fels Research Institute is followed by a critical review of the measurement of sarcopenia, which is a deficiency of muscle mass, and its implications for health. The only satisfactory data for total muscle mass come from one cadaver study of a small selected sample. Analyses in relation to health (mortality rates) are limited to indices of muscle mass of which the body mass index (BMI) and arm muscle area or circumference are the most important because large amounts of serial data are available for analysis. The association between low BMI values and increased mortality rates is well established. Multiple studies, some of large samples, indicate that the increased mortality in those with low BMI values at entry is not fully explained by smoking behavior or disease at entry. There are, however, contrary findings from one major study. Associations between arm muscle circumference or area with mortality rates have also been reported. Independent effects of low BMI and low arm muscle values on mortality rates could be due to effects of low fat‐free mass, particularly low muscle mass, on host defense mechanisms and risk factors for disease but few relevant data have been reported. © 1994 Wiley‐Liss,

ISSN:1042-0533    

DOI:10.1002/ajhb.1310060107

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

年代:1994

数据来源: WILEY

摘要:

AbstractIn order to identify relationships between changes in the body mass index (BMI) and those occurring in bone density with age, data from a sample of 2,075 Arizona retirees aged 60–90 years were compared by age and sex. Remodeling of the diaphysis of the radius follows a pattern that results in an increased diameter of the cortex and medullary cavity in both sexes. However, the resultant decrease in percentage cortical area (PCA) was greater in women than in men. The positive relationship between BMI and PCA is more pronounced in women, who begin to lose bone density earlier than men, and also lose it more rapidly. Despite the fact that average age at menopause is about 50 years and it is generally believed that bone loss slows within 5–10 years after menopause, average PCA values decline from 44% in 60–70 year old women to 37% in 80–90 year old Sun City women and to 36% in Tucson women. The decline in average PCA ranges from 45% in Sun City men and 46% in Tucson for 60–70 year old men to 43% and 42%, respectively, in 80–90 year olds. When the PCA values of women in four BMI categories are compared, cortical area increases with BMI, while medullary cavity values are similar across BMI categories. This relationship between BMI and PCA is much weaker in men. This pattern suggests more vigorous subperiosteal apposition in women with higher BMIs. Endosteal resorption does not seem to be as much affected by the BMI. An additional observation is that the BMIs of Sun City women are lower than those of Tucson women, although the decline in average values with age is very similar in the two populations, with a sharper decline from the 70–80 year group to the 80–90 year group than seen between the 60–70 year group and the 70–80 year group. Average BMIs of males are consistently higher than those of females in all age groups in the Sun City sample, but means for the sexes are very similar in the Tucsonans beyond 70 years. Sun City males of more advanced age are heavier than Tucson males, but the situation is reversed when women are similarly compared. ©

ISSN:1042-0533    

DOI:10.1002/ajhb.1310060108

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

年代:1994

数据来源: WILEY

摘要:

AbstractThe relationship of body fat distribution to serum cholesterol levels was evaluated in a sample of 3,040 Mexican Americans 18–74 years of age from the Hispanic Health and Nutrition Examination Survey (HHANES) conducted from 1982–1984. Fat distribution was determined by the ratio of trunk to extremity skinfold thicknesses, while the sum of skinfold thicknesses was used as an indicator of total body fat. Results of this study indicate that: 1) Mexican Americans are significantly fatter and have a higher trunk/extremity skinfold ratio than U.S. standards; 2) despite their higher level of total body fat and truncal fat, Mexican Americans have lower serum cholesterol levels than U.S. standards; 3) Mexican American males at the same percentile level of fatness or trunk/extremity skinfold ratio have significantly higher serum cholesterols than females, despite the fact that females have higher absolute values of fat and truncal fat than males; 4) among Mexican American males the association between truncal fat distribution and hypercholesteremia increases with level of fatness. In other words, in Mexican American males the association of truncal fat distribution with hypercholesteremia is accentuated by obesity. © 1994 Wiley‐Lis

ISSN:1042-0533    

DOI:10.1002/ajhb.1310060109

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

年代:1994

数据来源: WILEY

摘要:

AbstractThere are two main questions about the sequence of emergence of the permanent teeth in humans: 1) Why is there so much variation in sequence within human populations? (2) What is the adaptive or evolutionary significance of emergence sequence? Here, the human condition is considered by comparing us to other living primates and to our evolutionary past and considered in the light of Schultz's hypothesis that sequence of tooth emergence is adapted to rate of postnatal growth (Schultz AH. In JM Tanner (ed.) Human Growth, pp 1–20, 1960). Frequencies of individual pairwise sequences (e.g., M1I1vs. I1M1) in the emergence of the permanent dentition are described for N = 110Macaca nemestrina, and compared to N = 157Pan troglodytesand ≥6,000Homo sapiens.In addition, sequences of gingival emergence are reconstructed forAustralopithecusand earlyHomo. Trends observed across these catarrhine primates suggest that sequence and variability in sequence can be understood by a simple model of adaptation of tooth emergence to growth rate. As rate of postnatal growth slows, molars drift to later positions in sequence, either by always emerging late in sequence, or by varying in the direction of late emergence. “Augmented sequences” (sequences written with notations about variability) are important in recognizing evolutionary trends; further, they often alter perception of similarities and differences among taxa. Although samples are small,Australopithecus africanusresembles the rapidly developing generaMacacaandPanmore than it resemblesHomo sapiens. © 1994 Wiley

ISSN:1042-0533    

DOI:10.1002/ajhb.1310060110

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

年代:1994

数据来源: WILEY

摘要:

AbstractHuman dietary patterns and metabolic requirements are compared to those of nonhuman primate species in order to gain insights into the evolution of our nutritional needs. In general, primate diet quality (i.e., caloric and nutrient density) is inversely related to body size and total resting metabolic requirements (RMR). Humans, however, consume a diet of much higher quality than is expected for our size and metabolic needs. This energy‐rich diet appears to reflect an adaptation to the high metabolic cost of our large brain. Among primates, the relative proportion of resting metabolic energy used for brain metabolism is positively correlated with relative diet quality. Humans represent the positive extreme, having both a very high quality diet and a large brain that accounts for 20–25% of resting metabolism. Evidence from the hominid fossil record implies that major changes in diet and relative brain metabolism occurred with the emergence of the genusHomo. © 1994 Wiley‐Lis

ISSN:1042-0533    

DOI:10.1002/ajhb.1310060111

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

年代:1994

数据来源: WILEY