Heat Exposure, Heat-Related Symptoms and Coping Strategies among Elderly Residents of Urban Slums and Rural Vilages in West Bengal, India.

The impact of heat stress among the elderly in India-particularly the elderly poor-has received little or no attention. Consequently, their susceptibility to heat-related illnesses is virtually unknown, as are the strategies they use to avoid, or deal with, the heat. This study examined perceptions of comfort, heat-related symptoms, and coping behaviors of 130 elderly residents of Kolkata slums and 180 elderly residents of rural villages south of Kolkata during a 90-day period when the average 24-h heat indexes were between 38.6 °C and 41.8 °C. Elderly participants in this study reported being comfortable under relatively warm conditions-probably explained by acclimatization to the high level of experienced heat stress. The prevalence of most heat-related symptoms was significantly greater among elderly women, who also were more likely to report multiple symptoms and more severe symptoms. Elderly women in the rural villages were exposed to significantly hotter conditions during the day than elderly men, making it likely that gender differences in symptom frequency, number and severity were related to gender differences in heat stress. Elderly men and elderly village residents made use of a greater array of heat-coping behaviors and exhibited fewer heat-related symptoms than elderly women and elderly slum residents. Overall, heat measurements and heat-related symptoms were less likely to be significant predictors of most coping strategies than personal characteristics, building structures and location. This suggests that heat-coping behaviors during hot weather were the result of complex, culturally influenced decisions based on many different considerations besides just heat stress.

Individually experienced heat stress among elderly residents of an urban slum and rural village in India.

The elderly are one of the most vulnerable groups to heat-related illnesses and mortality. In tropical countries like India, where heat waves have increased in frequency and severity, few studies have focused on the level of stress experienced by the elderly. The study presented here included 130 elderly residents of Kolkata slums and 180 elderly residents of rural villages about 75 km south of Kolkata. It used miniature monitoring devices to continuously measure temperature, humidity, and heat index experienced during everyday activities over 24-h study periods, during hot summer months. In the Kolkata slum, construction materials and the urban heat island effect combined to create hotter indoor than outdoor conditions throughout the day, and particularly at night. As a result, elderly slum residents were 4.3 times more likely to experience dangerous heat index levels (≥ 45°C) compared to rural village elderly. In both locations, the median 24-h heat indexes of active elderly were up to 2°C higher than inactive/sedentary elderly (F = 25.479, p < 0.001). Among Kolkata slums residents, there were no significant gender differences in heat exposure during the day or night, but in the rural village, elderly women were 4 times more likely to experience dangerous heat index levels during the hottest times of the day compared to elderly men. Given the decline in thermoregulatory capacity associated with aging and the increasing severity of extreme summer heat in India, these results forecast a growing public health challenge that will require both scientific and government attention.

Using multiple correspondence analysis to identify behaviour patterns associated with overweight and obesity in Vanuatu adults.

OBJECTIVE: The present study evaluates the use of multiple correspondence analysis (MCA), a type of exploratory factor analysis designed to reduce the dimensionality of large categorical data sets, in identifying behaviours associated with measures of overweight/obesity in Vanuatu, a rapidly modernizing Pacific Island country. DESIGN: Starting with seventy-three true/false questions regarding a variety of behaviours, MCA identified twelve most significantly associated with modernization status and transformed the aggregate binary responses of participants to these twelve questions into a linear scale. Using this scale, individuals were separated into three modernization groups (tertiles) among which measures of body fat were compared and OR for overweight/obesity were computed. SETTING: Vanuatu.ParticipantsNi-Vanuatu adults (n 810) aged 20-85 years. RESULTS: Among individuals in the tertile characterized by positive responses to most of or all the twelve modernization questions, weight and measures of body fat and the likelihood that measures of body fat were above the US 75th percentile were significantly greater compared with individuals in the tertiles characterized by mostly or partly negative responses. CONCLUSIONS: The study indicates that MCA can be used to identify individuals or groups at risk for overweight/obesity, based on answers to simply-put questions. MCA therefore may be useful in areas where obtaining detailed information about modernization status is constrained by time, money or manpower.

Rolling Tobacco in Banana Leaves, Newspaper, or Copybook Paper Associated With Significant Reduction in Lung Function in Vanuatu.

In addition to the widespread availability of packaged cigarettes, the inhabitants of island nations of the Southwest Pacific frequently smoke commercially available loose tobacco using manufactured rolling papers, as well as locally grown tobacco rolled in manufactured rolling paper or wrapped in leaves, copybook paper, and newspaper. In this study, Vanuatu men who smoked local tobacco rolled in leaves, copybook paper, or newspaper showed significantly lower forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), and FEV1/FVC ratios than men who smoked packaged cigarettes, store-bought tobacco rolled in manufactured rolling paper, or who smoked locally grown tobacco rolled in manufactured rolling papers. The addition of toxins from these unusual tobacco-wrapping media produces lung function deficits similar to the pattern noted among tobacco smokers who also inhale smoke from burning biomass. Thus, public health initiatives should consider including strategies addressing the use of wrapping media among smokers in South Pacific island societies.

Ownership of consumer electronics is associated with measures of adiposity during health transition in Vanuatu.

OBJECTIVE: The Republic of Vanuatu, like many developing nations, is undergoing a rapid health transition. Our previous study identified several behavioral risk factors for the rising prevalence of obesity. Unexpectedly, daily time spent using television and radio was revealed as a protective factor for obesity in 2007. In this study, we sought to explore associations between ownership of consumer electronics (CE) and measures of adiposity in Vanuatu in 2011. METHODS: We surveyed 873 adults from five islands varying in level of economic development. Height, weight, and waist circumferences; triceps, subscapular, and suprailiac skinfolds; and percent body fat by bioelectrical impedance were measured. Ownership of eight types of CE, diet through 24-h dietary recall and leisure-time activity patterns were assessed using a questionnaire. RESULTS: Participants from more developed islands owned more types of CE, and revealed higher measures of adiposity on average as well as higher prevalence of obesity/central obesity. When controlling for demographic factors, and dietary and activity patterns, increased measures of adiposity and risk for obesity/central obesity were associated with ownership of cellphones, music players, televisions, video players, microwaves, and/or refrigerators. Positive correlations between CE ownership and measures of adiposity were mainly observed among men on the two most developed islands. CONCLUSIONS: The results of this study indicate a possible role of CE use in the rising prevalence of obesity and the shift to a sedentary lifestyle in Vanuatu and many other modernizing regions, where prevention efforts including education on healthy use of CE are imperative.

Larger FVC and FEV1 among Tibetans compared to Han born and raised at high altitude.

OBJECTIVES: This study compares forced vital capacity (FVC) and Forced Expiratory Volume at 1 Second (FEV1 ) of Tibetans with those of Han who were born and raised at high altitude. MATERIALS AND METHODS: FVC and FEV1 tests were conducted among 1,063 children and adolescents between the ages of 6 and 20 years, and 184 adults between the ages of 21 and 39 years who had lived their entire lives at 3200 m, 3800 m and 4300 m in Qinghai Provence, Peoples Republic of China. RESULTS: Even though FVC and FEV1 values of Han born and raised at high altitude are generally lower than those of Tibetans through age 15 in girls and age 16 in boys, differences are largely explained by variation in stature (height-squared) and chest circumference. Among older adolescents and adults, the FVC and FEV1 values of Tibetans are significantly larger than those of Han born and raised at high altitude; and are much larger than would be predicted, based on stature and chest circumference. DISCUSSION: These results indicate that the large FVC and FEV1 values of Tibetan adults develop primarily from an accelerated pattern of lung growth that begins during mid-to-late adolescence and possibly extends into young adulthood. This developmental pattern is not only distinct from that of Han born and raised at high altitude, but also from those of Andean Quechua and Aymara. The pace of lung function growth may therefore represent another feature distinguishing the Tibetan from the Andean pattern of adaptation to high altitude hypoxia. Because of this, a search for features in the Tibetan genome related to this lung function growth phenotype might be productive and important.

Stunting and the Prediction of Lung Volumes Among Tibetan Children and Adolescents at High Altitude.

This study examines the extent to which stunting (height-for-age Z-scores ≤ -2) compromises the use of low altitude prediction equations to gauge the general increase in lung volumes during growth among high altitude populations. The forced vital capacity (FVC) and forced expiratory volume (FEV1) of 208 stunted and 365 non-stunted high-altitude Tibetan children and adolescents between the ages of 6 and 20 years are predicted using the Third National Health and Nutrition Examination Survey (NHANESIII) and the Global Lung Function Initiative (GLF) equations, and compared to observed lung volumes. Stunted Tibetan children show smaller positive deviations from both NHANESIII and GLF prediction equations at most ages than non-stunted children. Deviations from predictions do not correspond to differences in body proportions (sitting heights and chest circumferences relative to stature) between stunted and non-stunted children; but appear compatible with the effects of retarded growth and lung maturation that are likely to exist among stunted children. These results indicate that, before low altitude standards can be used to evaluate the effects of hypoxia, or before high altitude populations can be compared to any other group, it is necessary to assess the relative proportion of stunted children in the samples. If the proportion of stunted children in a high altitude population differs significantly from the proportion in the comparison group, lung function comparisons are unlikely to yield an accurate assessment of the hypoxia effect. The best solution to this problem is to (1) use stature and lung function standards based on the same low altitude population; and (2) assess the hypoxic effect by comparing observed and predicted values among high altitude children whose statures are most like those of children on whom the low altitude spirometric standard is based-preferably high altitude children with HAZ-scores ≥ -1.

Impact of modernization on adult body composition on five islands of varying economic development in Vanuatu.

OBJECTIVE: The Republic of Vanuatu, similar to other South Pacific island nations, is undergoing a rapid health transition as a consequence of modernization. The pace of modernization is uneven across Vanuatu's 63 inhabited islands, resulting in differential impacts on overall body composition and prevalence of obesity among islands, and between men and women. In this study, we investigated (1) how modernization impacts body composition between adult male and female Melanesians living on four islands of varying economic development in Vanuatu, and (2) how body composition differs between adult Melanesians and Polynesians living on rural islands in Vanuatu. METHODS: Anthropometric measurements were taken on adult male and female Melanesians aged 18 years and older (n = 839) on the islands of Ambae (rural), Aneityum (rural with tourism), Nguna (rural with urban access), and Efate (urban) in Vanuatu, in addition to Polynesian adults on Futuna (rural). RESULTS: Mean measurements of body mass and fatness, and prevalence of obesity, were greatest on the most modernized islands in our sample, particularly among women. Additionally, differences between men and women became more pronounced on islands that were more modernized. Rural Polynesians on Futuna exhibited greater body mass, adiposity, and prevalence of obesity than rural Melanesians on Ambae. CONCLUSIONS: We conclude that Vanuatu is undergoing an uneven and rapid health transition resulting in increased prevalence of obesity, and that women are at greatest risk for developing obesity-related chronic diseases in urbanized areas in Vanuatu.

Adult lipids associated with early life growth in traditional Melanesian societies undergoing rapid modernization: a longitudinal study of the mid-20th century.

Both poor fetal development and accelerated post-natal growth have been linked to adult dyslipidemias in many studies conducted in developed societies. It is not known, however, whether these relationships only characterize populations with typical Western diets or if they also may develop in groups at the early stages of a dietary transition. Our longitudinal study of traditional rural populations in the Southwest Pacific during a period of extremely rapid modernization in diet and life-styles shows a nascent association between child growth retardation, subsequent growth acceleration, and adult lipid values in spite of a continuing prevalence of very low lipid levels. However, our results do not entirely conform to results from populations with "modern" diets. Outcome (i.e., young adult) cholesterol and triglyceride levels are more consistently related to initial measures of body fat and growth in body fat measures than with stature, while outcome apo A-1 is more consistently related to initial stature or stature growth than to measures of body fat. We suggest this may reflect a pattern characteristic of the initial stages of "modernization" associated with dietary change, with stronger and more pervasive relationships emerging only later as populations complete the dietary transition.

Responses of Han migrants compared to Tibetans at high altitude.

While many studies have compared Tibetans and low-altitude born Han living at high altitude, few have carefully controlled the chronological age at which lowlanders migrated, the length of time they had lived at high altitude, their nutrition, and their socio-economic status. This has produced an array of results that frequently do not support the hypothesis that Tibetans and Han show fundamental differences in their response to hypoxia. Unlike the situation in the Andes, only one study has tested the developmental adaptation hypothesis on the Qinghai-Tibetan plateau. This study shows that Tibetans and Han of the same age, who were born and raised in the same towns at the same altitudes, show considerable overlap in the individual distribution of [Hb], SaO2 and lung volumes. These results indicate that second-generation Han make substantial developmental adjustments to hypoxia that are not reflected in studies of first-generation migrants. Thus, there is a great need for further developmental studies to determine whether and/or how Han and Tibetan responses to hypoxia diverge, as well as for studies exploring whether Han and Tibetans who show similar responses also share genetic adaptations.

Modernization and the onset of overweight and obesity in Bougainville and Solomon Islands children: cross-sectional and longitudinal comparisons between 1966 and 1986.

This set of cross-sectional and longitudinal data from children and young adults in certain Bougainville and Solomon Islands populations undergoing rapid modernization during the period 1966-1986 reveals very different responses to essentially the same stimuli-the introduction and widespread availability of western dietary items and reductions in habitual activity. Our analyses of over 2,000 children and young adults first measured in 1966-1972, with follow-up surveys in 1968-1970 and 1985-1986, show changes in overweight/obesity in these communities have their onset around puberty, and are not related to differences in childhood growth stunting. The prevalence of overweight and obesity increased substantially during the period of this study among young adults, particularly women, and in groups with more Polynesian affinities, where the frequency of overweight (BMI ≥ 25) tripled over this 20-year interval. However, the BMI of the more Papuan groups on Bougainville remained remarkably stable, even though they were close to the epicenter of modernization during this period, the Bougainville Copper Mine.

A comparative analysis of arterial oxygen saturation among Tibetans and Han born and raised at high altitude.

This study compares resting arterial oxygen saturation as measured by pulse oximetry (Sp(O2)) among 818 Tibetans and 668 Han who were born and raised at altitudes between 3200 and 4300 m in Qinghai Province, Western China. Both Tibetans and Han show an increase in Sp(O2) values between the ages of 5 and 19 yr, and both groups show a decline after the third decade. However, mean, age-adjusted Sp(O2) values at rest do not differ significantly among growing Tibetans and Han aged 5 through 19 yr or among Tibetans and Han aged 20 through 51 yr. Therefore, the results of this study do not support the hypothesis that indigenous groups possess a superior arterial saturation while awake and at rest compared to lowlanders who have been born and raised at high altitude. Differences between adult Tibetan males and females approach statistical significance (females show higher values than males), while differences between adult Han males and females are not statistically significant. A review of the literature indicates that substantial interstudy variation exists in resting Sp(O2) values among Tibetans residing at high altitudes (between 2% and 4%, depending on the age of individuals measured) and may reflect differences in sample size, health of participants, instruments, probe location, and measurement protocols.

Growth of Han migrants at high altitude in central Asia.

Han Chinese of low-altitude descent have been living in Qinghai Province of Western China for at least two millennia. For most of this time they have lived at elevations under 2,500 m. However, during the last four decades an increasing number of Han have moved into high-altitude towns at elevations over 3,000 m, and some above 4,000 m. There are now sufficient numbers of Han descendants who have been born and raised at high altitude to allow a comparison of their morphological and physiological growth patterns with low-altitude Han to detect the effect of hypoxia. The field study reported here was conducted by collaborating Chinese and American researchers over a 6-year period, and included 1,227 Han living at high altitude in Qinghai and at low altitude near Beijing. This study demonstrates that Han born and raised at high altitude are smaller and lighter than those at low altitude-particularly as children and adolescents. Slower growth at high altitude may be a consequence of hypoxia, but it also corresponds to poorer economic conditions in rural Qinghai Province, and thus may reflect nutritional inadequacies. Differences in altitude and/or nutrition do not seem to affect thorax dimensions, since, relative to stature, chest dimensions are similar at both high and low altitudes. Nevertheless, lung volumes are higher among Han at high altitude, possibly reflecting the influence of hypoxia on alveolar growth. The hematological values of Han growing up at 3,200 m are not different from those at low altitude-an unusual finding relative to other low-altitude groups that may reflect population differences in response to hypoxia. At 3,800 m and 4,300 m, however, Han show elevated hemoglobin relative to Han at low altitude.

Environmental stress and adaptational responses: consequences for human health outcomes.

With the dramatic pace of modernization of the world's population, human adaptation as a theoretical construct and paradigm will likely become a focal scientific issue involving scientists from many disciplinary areas during the 21st Century. Macro and micro environments are in rapid flux and human populations are exposed to rapid change. The concept of adaptation, at least in the field of biological anthropology and human biology, will likely remain tied to evolutionary processes and concepts of selection and fitness. In this paper, we discuss the theoretical constructs of adaptation and adaptability and select three current examples from our ongoing research that involve studies of adaptation and evolutionary processes in modernizing populations in different locations worldwide.

Hematological differences during growth among Tibetans and Han Chinese born and raised at high altitude in Qinghai, China.

This study describes the hemoglobin concentration ([Hb]) and hematocrit (HCT) of over 1,000 Tibetan and Han children, adolescents, and young adults who were born and raised at 3,200 m, 3,800 m, or 4,300 m in Qinghai Province, western China. At 3,200 m, no altitude effect is evident in the hematological characteristics of either group. At 3,800 m and 4,300 m, both groups show [Hb] and HCT values that are above low-altitude norms. At both altitudes, Tibetan and Han children show no differences in the pattern of hematological response up to age 13. Among adolescents and young adults, however, the [Hb] and HCT of Han males and females are elevated compared to Tibetans. This indicates that the adolescent period may involve a divergence in the responses to hypoxia made by some individuals in these two groups. Also, many other adolescents and young adults in both groups show similar hematological characteristics, indicating that many Tibetans and Han share similar hematological responses to hypoxia.

Lung function of Han Chinese born and raised near sea level and at high altitude in Western China.

Forced vital capacity (FVC), forced expiratory volume at 1 second (FEV(1)), and FEV(1)/FVC ratios were determined for 531 individuals of Han Chinese descent living at low altitude (250 m) near Beijing and for 592 individuals of Han descent who were born and raised at three high altitudes (3,200 m, 3,800 m, 4,300 m) in Qinghai Province, P.R.C. The study included males and females, ages 6-51 years. Thorax widths, depths, and circumferences of Han females and males born and raised at high altitude are similar to those of low-altitude Han. On the other hand, high-altitude children and adolescents have larger relative sitting heights, indicating greater thorax lengths. After adjusting for this variation in morphology, mean FVC values among 6-21 year-old Han at high altitude are only between 136 mL (for females) and 173 ml (for males) greater than those determined at low altitude but the differences are statistically significant and are maintained consistently throughout the growth period. These data indicate that growth at high altitude produces small-to-moderate increases in lung volumes (about 6%) relative to genetically similar groups growing up at low altitude. In addition, there is no evidence that lung volume growth is accelerated relative to morphological growth among Han children born and raised at high altitude. Adults, 22-51 years, also show greater FVC values at high altitude but the size of the increase relative to Han at low altitude is variable (3% in males and 11% in females). Greater lung function at high altitude is unlikely to result from increased activity or lower pollution, and thus appears to be primarily a result of development in a hypoxic environment. Differences in FVC and FEV(1) at 3,200 m, 3,800 m, and 4,300 m are generally not significant, so that living at altitudes between 3,200 m and 4,300 m appears to have little additional effect on volumetric growth.

Morphological growth of Han boys and girls born and raised near sea level and at high altitude in western China.

This study compares the morphological characteristics of Han children, adolescents, and young adults who were born at 250 m near Beijing and at three high altitudes in Qinghai Province, Peoples Republic of China (3,200 m, 3,800 m, and 4,300 m). From ages 6 through 15, Han children growing up at high altitudes are significantly shorter, lighter, have less fat, and are less muscular than Han children growing up at low altitude. However, older adolescents and young adults show no such altitude differences. Younger adolescents and children in this study were all born after the government economic reforms of 1978. These reforms had a greater impact on the growth of children in and around large cities than on those in more remote areas. Therefore, the altitude differences in size among Han children ages 15 and younger may be a consequence of regional variation in health and nutrition, rather than due to the influence of hypoxia. There are no altitude-related differences in thorax dimensions among Han children, adolescents, or young adults. This suggests that hypoxia does not affect the thorax growth of Han children. Am. J. Hum. Biol. 12:665-681, 2000. Copyright 2000 Wiley-Liss, Inc.