The effects of aging and secular trend on adult stature in rural western Ireland

Cross-sectional data, consisting of anthropometric measurements for 347 adult males and 261 adult females in western Ireland measured during the 1930s, were used to determine the effects of aging and secular change upon stature. Estimates of statural loss due to aging were obtained using partial regression of stature on age while controlling for subischial length, and regression of the difference between observed stature and maximum predicted stature on age. Males show the effects of aging to a greater extent than do females. After correction for the effects of aging, the adjusted values of stature were regressed on age to estimate secular trend of stature. For males, there is a general increase of stature with time, excepting those born around 1878, while females generally show random variation with time. Both male and female adjusted stature decrease sharply around 1878, for which alternative historical explanations are proposed, relating to differential migration and survival.     

Craniofacial dimensions in children in rural Oaxaca, southern Mexico: secular change, 1968-2000

The objective of this investigation was to analyze the underlying cause(s) of secular changes in craniofacial dimensions among indigenous children in an isolated community in Oaxaca, southern Mexico, between 1968-2000. Subjects were schoolchildren resident in a rural, agrarian, Zapotec-speaking community in the Valley of Oaxaca, previously characterized as mildly-to-moderately undernourished with growth-stunting in 1968 and 1978. In 2000, children had experienced a secular increase in height compared with two prior growth surveys. Four craniofacial dimensions (head length, head breadth, and bizygomatic and bigonial breadths) were measured during anthropometric surveys of schoolchildren aged 6-13 years in 1968, 1978, and 2000. Cephalic and zygomandibular indices were calculated. Samples by survey were: 1968, 151 males and 157 females; 1978, 179 males and 184 females; and 2000, 180 males and 186 females. The analysis was based on a total of 1,037 children. Multivariate analysis of covariance was used to assess secular trend effects, with height, age, and age2 as covariates by sex. Over the interval of 32 years, significant secular changes occurred in craniofacial dimensions and one index: 1) head length was shorter in boys and girls; 2) bizygomatic breadth was narrower in boys and girls; 3) head breadth increased over time only among girls; 4) brachycephalization increased significantly in a linear manner among both sexes; and 5) the zygomandibular index decreased significantly only in boys. Thus, the cranial complex remodeled to a shorter head length, both relatively (brachycephalization) and absolutely. Remodeling over time also resulted in a narrower face, with the midface changing at about the same rate as the lower face (i.e., mandible). Secular changes are generally recognized as multifactorial. Changes in the cephalic index and cranium over time in schoolchildren in an isolated rural agrarian Zapotec-speaking community in the Valley of Oaxaca suggest that the underlying forces for the secular change are associated: 1) decreased food (maize) coarseness or grit content (masticatory stress), and 2) relaxed natural selection, resulting in 3) a greater role for developmental plasticity.     

Sex and gender differences in secular trend of body size and frame indices of Lithuanians

In Lithuania, as in many other European countries, positive secular trend of body size became especially expressed at the middle of XX. century. The analysis showed the evident secular trend in height of adult Lithuanians since the end of XIX. century till 2001 from 163.5 till 181.3 cm in males and from 153.3 cm till 167.5 cm in females. Concerning growth and development of children, during the 1925-2001 period especially obvious acceleration of height was determined at the middle of adolescence due to much earlier sexual maturation at the end of XX. century. Secular trend of body height was more expressed in males of all ages, nevertheless this process stabilized in both sexes during the last decades. While comparing secular changes in BMI of adolescent Lithuanian girls and boys between the 1925-2001 period, the evident sexual differences in secular changes were determined from the middle of pubescence: the course of changes in BMI during the XX. century was nearly the same in both sexes, but at the end of XX. century older adolescent girls became obviously thinner compared with the changes of BMI in boys of the same age. A very similar trend in BMI of adult Lithuanian women since 1980 till 2002 was also detected. This phenomenon could be more related with the changes in life stile, modern-day canons for unrealistically thin female's body and strong social pressure on women today.     

Variation of annual apparent survival and detection rates with age,year and individual identity in male Weddell seals (Leptonychotes weddellii) from long-term mark-recapture data

Exploring age- and sex-specific survival rates provides insight regarding population behavior and life-history trait evolution. However, our understanding of how age-specific patterns of survival, including actuarial senescence, compare between the sexes remains inadequate. Using 36 years of mark-recapture data for 7,516 male Weddell seals (Leptonychotes weddellii) born in Erebus Bay, Antarctica, we estimated age-specific annual survival rates using a hierarchical model for mark-recapture data in a Bayesian framework. Our male survival estimates were moderate for pups and yearlings, highest for 2-year-olds, and gradually declined with age thereafter such that the oldest animals observed had the lowest rates of any age. Reports of senescence in other wildlife populations of species with similar longevity occurred at older ages than those presented here. When compared to recently published estimates for reproductive Weddell seal females, we found that peak survival rates were similar (males: 0.94, 95% CI = 0.92–0.96; females: 0.92, 95% CI = 0.93–0.95), but survival rates at older ages were lower in males. Age-specific male Weddell seal survival rates varied across years and individuals, with greater variation occurring across years. Similar studies on a broad range of species are needed to contextualize these results for a better understanding of the variation in senescence patterns between the sexes of the same species, but our study adds information for a marine mammal species to a research topic dominated by avian and ungulate species.     

Adult stature and age at menarche in Zapotec-speaking communities in the Valley of Oaxaca,Mexico, in a secular perspective

Adult stature and the age at menarche among individuals from Zapotec-speaking communities in the Valley of Oaxaca in southern Mexico are considered in a secular perspective. Four sets of observations are utilized: (1) adult stature in males and females from five rural communities; (2) age at menarche in adult women and school girls from a single rural community; (3) earlier studies of adult stature in the Valley of Oaxaca; and (4) estimated stature from long bones excavated in various archaeological sites in the Valley of Oaxaca. There were no significant differences among the five communities for stature; hence, the data were pooled for analysis and comparison. Results of linear regression of stature and stature adjusted for the estimated effects of aging after 30 years of age on year of birth indicate negligible secular changes in either sex. Comparisons with statures from earlier surveys, the earliest dates to 1899, also indicate negligible changes. When adult women are grouped according to age, there are no differences in mean ages at menarche between the older and younger women. Mean age at menarche for the total adult sample is 14.53 ± 0.08 years, which compares favorably with the probit estimate for school girls, 14.70 ± 0.32 years. These results thus suggest virtually no secular change in adult size and maturity of the Zapotec-speaking population in the Valley of Oaxaca over the past 80 years. Differences in stature between contemporary populations and estimated statures from long bones from several archaeological sites in Oaxaca are small, and thus suggests little secular change over the past one to two–thousand years.     

Aging, transition, and estimating the global burden of disease

Background

The World Health Organization''s Global Burden of Disease (GBD) reports are an important tool for global health policy makers, however the accuracy of estimates for countries undergoing an epidemiologic transition is unclear. We attempted to validate the life table model used to generate estimates for all-cause mortality in developing countries.

Methods and Results

Data were obtained for males and females from the Human Mortality Database for all countries with available data every ten years from 1900 to 2000. These provided inputs for the GBD life table model and served as comparison observed data. Above age sixty model estimates of survival for both sexes differed substantially from those observed. Prior to the year 1960 for males and 1930 for females, estimated survival tended to be greater than observed; following 1960 for both males and females estimated survival tended to be less than observed. Viewing observed and estimated survival separately, observed survival past sixty increased over the years considered. For males, the increase was from a mean (sd) probability of 0.22 (0.06) to 0.46 (0.1). For females, the increase was from 0.26 (0.06) to 0.65 (0.08). By contrast, estimated survival past sixty decreased over the same period. Among males, estimated survival probability declined from 0.54 (0.2) to 0.09 (0.06). Among females, the decline was from 0.36 (0.12) to 0.15 (0.08).

Conclusions

These results show that the GBD mortality model did not accurately estimate survival at older ages as developed countries transitioned in the twentieth century and may be similarly flawed in developing countries now undergoing transition. Estimates of the size of older-age populations and their attributable disease burden should be reconsidered.     

Secular change in growth of native children and adolescents at high altitude I. Puno,Peru (3800 meters)

A cross sectional sample of 969 native males from Puno (Peru), altitude 3800 m, ranging in age from 7–20 years, and studied for body height, weight, sitting height, leg length, and chest circumference in 1980, were compared, from the point of view of secular trend, with another cross sectional sample of 992 native males from the same place, which were investigated in 1945. In addition, similar observations were carried out in 1980, in a group of 112 females. The data indicate that in Puno there has been no secular increment in the adult body size. However for all ages between 7 and 19 years, body weight and height were significantly greater in 1980 than in 1945. This may be due to earlier sexual maturation in the present generation.     

Mortality differentials by size of place and sex in Pennsylvania for 1960 and 1970

Abstract

Factors which affect mortality rates differ by size of place of residence. Mortality differentials were examined by size of place of residence for two recent time periods. A new method of rate adjustment was employed to eliminate the confounding effects of differences in age composition upon rates. Positive associations between adjusted mortality rates and size of place were evident in both metropolitan and nonmetropolitan counties. The smallest places in metropolitan counties had the lowest adjusted mortality rates. The adjusted mortality rates for males exceeded those for females in each size of place. These patterns were evident in data for both 1960 and 1970. The adjusted mortality rates for females declined by greater percentages than did those for males in each size of place between 1960 and 1970.     

Sex ratio, survival and territorial behaviour of polygynous Hen Harriers Circus c. cyaneus in Orkney

Polygyny is widespread among Orkney's Hen Harriers Circus cyaneus . From 1975–81, it was associated with a sex ratio estimated from resightings of colour-marked birds up to six years of age to be 29 females:ten males. The sex ratio of fledglings changed significantly from a greater proportion of females in the 1950s and early 1960s to a greater proportion of males subsequently. The mean estimated 'survival' rates (birds colour-marked in Orkney which were seen there in later years) of males and of females 0–2 years old were 14 and 29%. The mean estimated annual survival rates of males and females from 2–6 years old were 72 and 90%. It is suggested that the uneven sex ratio resulted in more frequent intra-sexual encounters and displays by females. The results of temporary removals of two females (immediately replaced) and of two males (not replaced) in spring indicates that there was a shortage of males in the population.     

The Great Chinese Famine Leads to Shorter and Overweight Females in Chongqing Chinese Population After 50 Years

This study investigated a possible association between early nutritional status during the famine, and the risk of overweight and obesity in adulthood in Chongqing Chinese population. The body weight, height, and BMI data were obtained from records of population (17,023) that had annual physical evaluations in the Public Health Center (in our hospital). Subjects born during 1956–1964 were divided into three groups: toddler group, all subjects who were born 1–3 years before the famine (1956–1958); gestational group, who were born during the famine period (1959–1961), and control group, who were born after the famine (1962–1964). The body weight and BMI were significantly higher, but the body height was significantly lower in the toddler and gestational groups (P < 0.05) in the female population as compared to the control group. The odds ratio of being overweight in females is more pronounced in the toddler group (1.48 times, 95% confidence interval (CI): 1.288–1.689) than in the gestational group (1.26 times, 95% CI: 1.089–1.457). The odds ratio of being obese in females is significantly higher in the toddler group (1.46 times, 95% CI: 1.288–1.689) than the control group. For males, the famine had no impact at all on the adulthood body weight in males. The Great Chinese Famine that affected the Chongqing population during 1959–1961 leads to shorter and overweight females, and the former is a risk factor for increased BMI in Chongqing. Second, the famine seems to be producing shorter but slimmer males in Chongqing. Furthermore, toddler's and maternal's malnutrition during the famine had important late consequences on the health status.     

Secular trends in childhood obesity in Denmark during 50 years in relation to economic growth

Objective: Our aim was to examine whether secular trends in childhood overweight and obesity during five decades could be explained by economic growth. Research Methods and Procedures: Annual measurements of height and weight were available for all children born between 1930 and 1983 attending primary school in the Copenhagen Municipality: 165,389 boys and 163,609 girls from the age of 7 through 13 years. After computerization, we calculated BMI (kg/m²) and estimated the prevalence of overweight and obesity, according to international age‐ and gender‐specific criteria, by year of birth and of measurement, and separately by each age group and gender. Economic growth was indicated by the Gross National Product and the overall consumption per capita, adjusted for inflation. Results: The prevalence of overweight occurred in phases: an increase from 1930 until the 1950s, followed by a plateau period between the 1950s and the 1960s and a steep increase thereafter. This pattern was apparent across all age groups and in both genders. Obesity trends showed a similar phase pattern; the prevalence remained relatively stable from 1930 until the 1940s, increased until the mid‐1950s, followed by a plateau until 1965, and thereafter a second steep increase. Obesity trends were similar among boys across all age groups, although only among girls from 11 to 13 years of age. In both genders, increments were most pronounced in the upper BMI percentiles. After stagnation until 1947, the economic growth indicators showed a steady increase; i.e., after the first increase started in overweight and obesity, whether analyzed by year of birth or year of measurement, there were no indications of phases in the rise thereafter. Discussion: Prevalence of overweight and obesity among Danish children rose in phases, which were not paralleled by trends in economic growth. The macroeconomic growth indicators seem inappropriate as proxies for the environmental exposures that have elicited the obesity epidemic.     

Has mortality from melanoma stopped rising in Australia? Analysis of trends between 1931 and 1994.

OBJECTIVE--To describe recent trends in mortality from melanoma in Australia. DESIGN--An analysis of trends in age standardised and age and sex specific mortalities by year of death and median year of birth (cohort). SETTING--Australia. SUBJECTS--All deaths from melanoma registered in Australia between 1931 and 1994. RESULTS--Melanoma mortality rose steadily from 1931 to 1985. From 1959 the annual rate of increase was 6.3% in men and 2.9% in women, resulting in mortalities of 4.82 and 2.51 per 100,000 person years in 1985 and 1989, respectively. Mortalities for both sexes seem to have plateaued from June 1985 onwards. In 1990-4 the rate rose by 3.7% in men to 5.00 per 100,000 and in women it fell by 5.2% to 2.38 per 100,000. The non-significant increase after 1985 in mortality in men was restricted to those aged over 70 years of age, whereas the fall in rates in women was mostly in those aged under 55 years. This pattern was generally reflected in the state trends, though with some variation: rates for women in Queensland had peaked in the late 1970s; while rates for men in New South Wales continued to rise in 1990-4, placing them above those for Queensland. Examination of mortalities specific for age, period, and cohort for Australia as a whole showed several salient features. Rates in men rose steeply in cohorts born before about 1930; were stable in cohorts born between 1930 and 1950; and fell in more recent cohorts. Rates in women showed similar changes but about five years earlier. CONCLUSION--Melanoma mortality in Australia peaked in about 1985 and has now plateaued. On the basis of trends in cohorts it can be expected to fall in coming years.     

Forty years trends in timing of pubertal growth spurt in 157,000 Danish school children

Background

Entering puberty is an important milestone in reproductive life and secular changes in the timing of puberty may be an important indicator of the general reproductive health in a population. Too early puberty is associated with several psychosocial and health problems. The aim of our study was to determine if the age at onset of pubertal growth spurt (OGS) and at peak height velocity (PHV) during puberty show secular trends during four decades in a large cohort of school children.

Methods and Findings

Annual measurements of height were available in all children born from 1930 to 1969 who attended primary school in the Copenhagen Municipality. 135,223 girls and 21,612 boys fulfilled the criteria for determining age at OGS and age at PHV. These physiological events were used as markers of pubertal development in our computerized method in order to evaluate any secular trends in pubertal maturation during the study period (year of birth 1930 to 1969). In this period, age at OGS declined statistically significantly by 0.2 and 0.4 years in girls and boys, respectively, whereas age at PHV declined statistically significantly by 0.5 and 0.3 years in girls and boys, respectively. The decline was non-linear with a levelling off in the children born between 1940 and 1955. The duration of puberty, as defined by the difference between age at OGS and age at PHV, increased slightly in boys, whereas it decreased in girls.

Conclusion

Our finding of declining age at OGS and at PHV indicates a secular trend towards earlier sexual maturation of Danish children born between 1930 and 1969. Only minor changes were observed in duration of puberty assessed by the difference in ages at OGS and PHV.     

Tooth size variation related to age in Amboseli baboons

We measured the molar size from a single population of wild baboons from Amboseli (Kenya), both females (n=57) and males (n=50). All the females were of known age; the males represented a mix of known-age individuals (n=31) and individuals with ages estimated to within 2 years (n=19). The results showed a significant reduction in the mesiodistal length of teeth in both sexes as a function of age. Overall patterns of age-related change in tooth size did not change whether we included or excluded the individuals of estimated age, but patterns of statistical significance changed as a result of changed sample sizes. Our results demonstrate that tooth length is directly related to age due to interproximal wearing caused by M2 and M3 compression loads. Dental studies in primates, including both fossil and extant species, are mostly based on specimens obtained from osteological collections of varying origins, for which the age at death of each individual in the sample is not known. Researchers should take into account the phenomenon of interproximal attrition leading to reduced tooth size when measuring tooth length for ondontometric purposes.     

Morphometric variation of the skull during postnatal development in the Lowland European bisonBison bonasus bonasus

We studied the variation of linear measurements and skull capacity in Lowland European bisonBison bonasus bonasus (Linnaeus, 1758) during postnatal development, and the dependencies of the parameters in relation to sex, age, and body mass of the animals. Material consisted of 599 bison skulls (310 males and 289 females), within the age range of 1 month to 21 years (males) and to 27 years (females). In the group of calves to 1 year old, no sex connected differences in skull measurements were observed, whereas the skull capacity in older calves was significantly larger (0.01>p>0.001) in males than in females. From the third year of life, most skull measurements display characteristics of sexual dimorphism. Skull development in both sexes is most intensive during the first three years of life, and slows from the age of 5. In older individuals of both sexes (≥ 6 years), orbital breadth continues growing and, in females, breadth of splanchnocranium continues increasing. Growth in a bison’s skull capacity is most intensive up to the third year of life and slows from the age of 5. During postnatal development, a bison skull grows proportionally except the neurocranium, which grows slightly slower in comparison with basal length and its development finishes earlier than that of splanchnocranium. In ontogenesis, a bison skull grows much slower compared to body mass. In relation to body mass, skull capacity and the height of neurocranium grow most slowly while orbital breadth grows most intensively. The results obtained were compared with data on skull sizes of bison born in 1930–1950 and bred in captivity and with skulls of the American bisonBison bison. Inbreeding is probably responsible for some types of phenotypic abnormalities in the skull which appear in modern European bison.     

Finding from Asia, Australia, Europe, and North Amercia on secular change in mean height of children, youths, and young adults.

Studies conducted during the past century in Australia, Canada, Japan, Norway and the United States indicate that the magnitude of secular increase in mean height rose with advancing age from childhood to mid-adolescence. Comparisons for a period approximating two-thirds of a century yield average increases in mean height of 12.2 cm for female youths age 12 years, and 12.5 cm for male youths age 14 years; for the same calendar span, the amount of secular increase in mean height declines from mid-adolescence to early adulthood. Comparisons of Belgian females, spanning a period approximating 130 years, yield increases in mean height of 18.1 cm at age 12 years, 11.9 cm at age 16 years, and 3.7 cm in early adulthood. For a period of 90 years, increases obtained on United States White males are 14.8 cm at age 14 years, 8.8 cm at age 17 years, and 5.3 cm in early adulthood. These and other displayed findings show clearly that the search for causes of secular change should take particular account of a phenomenon widespread among human populations, i.e., the phenomenon of childhood and early adolescent growth in body height proceeding at a faster pace in recent decades than about a century ago.     

The feral goats of Raoul Island,and some effects of hunting on their body size and population density

Abstract

A campaign to eradicate goats (Capra hircus L.) was begun in August–October 1972 on Raoul Island, Kermadec group, 1000 km north-east of New Zealand. Of a total of 1286 animals killed, 155 were examined and dissected. The coat colour of 88% was pradominandy black, and of these 80% were patterned with white and/or brown. The hair was short in 85% of the goats, but a few males were shaggy all over. No throat tassels or other features of improved breeds were seen. Both sexes were fecund by 1 year of age. Conceptions occurred up to the winter solstice, but none was recorded for at least 4 months after it. Older females conceived earlier than young ones. Females more than 2 years old were 53% of all fecund females, and produced 66% of all kids born. Productivity was estimated to be 83 or 94 kids per year per 100 females of breeding age, depending on the criteria used. Eviscerated body weight, body length, shoulder height, and horn length all showed clear sexual dimorphism, and all increased with age up to 3 years. Kidney fat increased with age only in males. At the time of sampling, female fatness was not related to reproductive state. In areas which had been hunted during the past decade the population was least dense, there was a higher proportion of young animals, the growth rate up to 1 year old was greater, and adults were larger, age for age, than elsewhere on the island.     

Lifetime fitness and age‐related female ornament signalling: evidence for survival and fecundity selection in the pied flycatcher

Ornaments displayed by females have often been denied evolutionary interest due to their frequently reduced expression relative to males, habitually attributed to a genetic correlation between the sexes. We estimated annual and lifetime reproductive success of female pied flycatchers (Ficedula hypoleuca) and applied capture–mark–recapture models to analyse annual survival rates in relation to the patterns of expression (absence/presence) of an ornament displayed by all males and a fraction of females. Overall, the likelihood of expressing the ornament increased nonlinearly with female age and was due to within‐individual variation, not to the selective appearance or disappearance of ornament‐related expression of phenotypes in the population. Accordingly, expressing the forehead patch in a given year did not influence survival probability. However, those females expressing the ornament at early ages (1–2 years old) enjoyed survival advantages throughout lifetime. Although ornamented females had higher lifetime fecundity and fledging success, their yearly reproductive performance, in terms of fledging productivity, decreased as they aged so that, late in life, ornamented females reared fewer offspring than nonexpressing females of the same age. In addition, both strategies (expressing vs. not expressing the trait) returned similar fitness payoffs in terms of recruited offspring. Our results support the hypothesis that fecundity and survival selection are involved in the displaying of this ‘male’ ornament by females.     

Fluoride in drinking water and osteosarcoma incidence rates in the continental United States among children and adolescents

IntroductionIt has been suggested that fluoride in drinking water may increase the risk of osteosarcoma in children and adolescents, although the evidence is inconclusive. We investigated the association between community water fluoridation (CWF) and osteosarcoma in childhood and adolescence in the continental U.S.MethodsWe used the cumulative osteosarcoma incidence rate data from the CDC Wonder database for 1999–2006, categorized by age group, sex and states. States were categorized as low (≤30%) or high (≥85%) according to the percentage of the population receiving CWF between 1992 and 2006. Confidence intervals for the incidence rates were calculated using the Gamma distribution and the incidence rates were compared between groups using Poisson regression models.ResultsWe found no sex-specific statistical differences in the national incidence rates in the younger groups (5–9, 10–14), although 15–19 males were at higher risk to osteosarcoma than females in the same age group (p < 0.001). Sex and age group specific incidence rates were similar in both CWF state categories. The higher incidence rates among 15–19 year old males vs females was not associated with the state fluoridation status. We also compared sex and age specific osteosarcoma incidence rates cumulated from 1973 to 2007 from the SEER 9 Cancer Registries for single age groups from 5 to 19. There were no statistical differences between sexes for 5–14 year old children although incidence rates for single age groups for 15–19 year old males were significantly higher than for females.ConclusionOur ecological analysis suggests that the water fluoridation status in the continental U.S. has no influence on osteosarcoma incidence rates during childhood and adolescence.     

Mortality estimates for South Kampala based on 1980 Uganda Population Census

In the absence of vital statistics data, analysis of the 1980 Uganda Population Census for South Kampala was able to provide estimates of infant, child, and adult mortality. Indirect techniques yielded estimated 1q0 values of 0.0860 for male infants, 0.0680 for female infants, and 0.0774 for infants of both sexes. The infant mortality rate estimated for 1980 is somewhat higher than that estimated for Kampala city in 1969 (0.0750), supporting medical professionals' opinion that infant mortality increased during the 1970s due to political and economic factors in Uganda and the consequent deterioration of health services. Child mortality (4q1), estimated in this study as 0.0491, appears to have declined during the 1970s; however, this unexpected finding may reflect differences in coverage and content errors in the 2 sets of data for 1969 and 1980. Adult mortality, based on the estimated survival rates from paternal and maternal orphanhood data and those from adjusted 12 values, is slightly lower than those for infant and child mortality. Expectation of life at birth estimates from various techniques show clearly that females have lower patterns of mortality than males. The estimated life expectation is 54.7 years for males, 59.3 years for females, and 57.0 years for both sexes. Overall, these estimates indicate a need for further reductions in mortality in Uganda as part of the overall development effort.