Closing the Womb Door: Contraception Use and Fertility Transition Among Culturally Tibetan Women in Highland Nepal

From the Ground Up: A Multidisciplinary Approach to Past Fertility and Population Narratives

Population dynamics form a crucial component of human narratives in the past. Population responses and adaptations not only tell us about the human past but also offer insights into the present and future. Though an area of substantial interest, it is also one of often limited evidence. As such, traditional techniques from demography and anthropology must be adapted considerably to accommodate the available archaeological and ethnohistoric data and an appropriate inferential framework must be applied. In this article, I propose a ground-up, multidisciplinary approach to the study of past population dynamics. Specifically, I develop an empirically informed path diagram based on modern fertility interactions and sources of past environmental, sociocultural, and biological evidence to guide high-resolution case studies. The proposed approach is dynamic and can evolve in response to data inputs as case studies are undertaken. In application, this approach will create new knowledge of past population processes which can greatly enhance our presently limited knowledge of high-frequency, small-scale demographic fluctuations, as well as contribute to our broader understanding of significant population disturbances and change throughout human history.

Childhood growth and education migration among ethnic Tibetan children from Nepal

BACKGROUND

Ethnographic work among high altitude populations has shown that children are highly mobile-the most recent expression of this is the educational migration of children born at high altitude to boarding schools at lower altitudes. The impact of these patterns of migration on size for age are unknown.

AIM

We investigated the association between growth in weight and height and educational migration in ethnic Tibetan children living in and out of their natal communities.

SUBJECTS AND METHODS

Five hundred and fifty eight children ages three to sixteen from the Nubri Valley, Nepal participated in this study. Three hundred children were living in natal villages and 258 were attending boarding schools in Kathmandu. Height, weight, and skinfold thicknesses were collected and matched to demographic data from the community.

RESULTS

There was no association between altitude of family residence and size for age z-scores. Males had lower z-scores than females; z-scores for both groups declined with age. Differences in size for age among children in boarding schools were associated with two factors: sex and type of boarding school (individual sponsor or group funded). Individuals attending individually sponsored schools had greater size for age compared to children in group funded schools or in their natal villages; younger children in collectively funded schools were smaller than village peers.

CONCLUSIONS

Despite popular perceptions, educational outmigration in Himalayan communities may not be associated with improved child growth outcomes and investment in community level schools may be a practical solution for improving child growth and physical and mental health.

Repeatability of adaptive traits among ethnic Tibetan highlanders

OBJECTIVES

Connecting traits to biological pathways and genes relies on stable observations. Researchers typically determine traits once, expecting careful study protocols to yield measurements free of noise. This report examines that expectation with test-retest repeatability analyses for traits used regularly in research on adaptation to high-altitude hypoxia, often in settings without climate control.

METHODS

Two hundred ninety-one ethnic Tibetan women residing from 3500 to 4200 m in Upper Mustang District, Nepal, provided three observations of hemoglobin concentration, percent of oxygen saturation of hemoglobin, and pulse by noninvasive pulse oximetry under conditions designed to minimize environmental noise.

RESULTS

High-intraclass correlation coefficients and low within-subject coefficients of variation reflected consistent measurements. Percent of oxygen saturation had the highest intraclass correlation coefficient and the smallest within-subject coefficient of variability; measurement noise occurred mainly in the lower values. Hemoglobin concentration and pulse presented slightly higher within-subject coefficients of variation; measurement noise occurred across the range of values. The women had performed the same measurements 7 years earlier using the same devices and protocol. The sample means and SD observed across 7 years differed little. Hemoglobin concentration increased substantially after menopause.

CONCLUSIONS

Analyzing repeatability features of traits may improve our interpretation of statistical analyses and detection of variation from measurement or biology. The high levels of measurement repeatability and biological stability support the continued use of these robust traits for investigating human adaptation in this altitude range.

Nomadic Tibetan women's reproductive health: findings from cross-sectional surveys with a hard-to-reach population

Background

Western China has undergone substantial sociodemographic change, yet little is known about the health status of ethnic minority populations living in these areas.

Methods

We report findings from two cross-sectional surveys conducted with female Tibetan nomads living in rural areas of Western China/Eastern Tibet. We present results of descriptive analyses of data collected from reproductive-aged females who attended community health fairs in 2014 (n = 193) and 2016 (n = 298).

Results

On average, sexual debut preceded marriage among study participants, with fertility near replacement levels (2.7 and 2.1 in 2014 and 2016, respectively). Contraceptive use was common, and dominated by use of IUDs and female sterilization. Although over three-quarters (76%) of 2016 survey participants reported ever having at least one sexually transmitted infection (STI) symptom, there was low awareness of STIs (59%) and action to prevent STIs (21%). Younger women (< 40) were more likely to report having had had an STI symptom, as compared to older women (84% versus 71%; p < 0.05).

Conclusions

We demonstrate feasibility of collecting data with this hard-to-reach population. Reporting of STI symptoms warrants further investigation to identify and address health conditions in this population of Tibetan nomadic women, especially amidst broader social and contextual changes that may affect the Tibetan population.

Western China has undergone substantial sociodemographic change, yet little is known about the health status of ethnic minority populations living in these areas. We report findings from two cross-sectional surveys conducted with female Tibetan nomads living in rural areas of Western China/Eastern Tibet. We present results of descriptive analyses of data collected from reproductive-aged females who attended community health fairs in 2014 (n = 193) and 2016 (n = 298). On average, sexual debut preceded marriage among study participants, with fertility near replacement levels (2.7 and 2.1 in 2014 and 2016, respectively). Contraceptive use was common, and dominated by use of IUDs and female sterilization. Although over three-quarters (76%) of 2016 survey participants reported ever having at least one sexually transmitted infection (STI) symptom, there was low awareness of STIs (59%) and action to prevent STIs (21%). Younger women (less than 40 years old) were more likely to report having had had an STI symptom, as compared to women over 40 years old (84% versus 71%; p < 0.05). We demonstrate feasibility of collecting data with this hard-to-reach population. Reporting of STI symptoms warrants further investigation to identify and address health conditions in this population of Tibetan nomadic women, especially amidst broader social and contextual changes that may affect the Tibetan population.

Trekking and toddlers: Towards a biocultural analysis of growth among infants and young children in a rural region of the Himalayas

OBJECTIVES

Rapid socioeconomic change, associated with development and a growing tourism industry is occurring across the Himalayas. The health impact of this rapid economic development is poorly understood, especially for infants and young children. This study investigated the associations between village level economic differences as indexed by economic development and tourism engagement on infant and young child growth and health in a population of ethnic Tibetans living in the western Himalayas of Nepal.

METHODS

One hundred and fifty nine infants and young children (ages 1-24 months) were enrolled. Anthropometric data (height, weight, triceps skinfold thickness) were collected at a single time point. Village level measurements of tourism and market engagement were incorporated into a scale measuring tourism, healthcare, trail access, agriculture, and involvement in medicinal trade. Village level disease patterns were calculated from morbidity and mortality recalls collected since 2003.

RESULTS

There were no significant associations between infant weight for age z-score (WAZ), length for age z-score (LAZ), or weight-for-length for age z-score (WLZ) and village altitude, village economic development score, or engagement in tourism. Males had significantly higher LAZ, WAZ, and WLZ compared to females; only females showed a decline in LAZ with age. Triceps skinfold thickness z-score (ZTSF) was inversely associated with village level economic development score in male but not female infants; females ZTSF was positively associated with IYC age.

CONCLUSIONS

While overall size for age indices (WAZ, LAZ, WLZ) were not associated with altitude or village economic development in this population, ZTSF was inversely associated with village economic development in males but not females.

Pragmatics of everyday life: A qualitative study of induced abortion among Tibetan women in Lhasa

Many abortions are performed annually in the People's Republic of China, where the practice is legal, largely safe, and readily available. In this article we present a qualitative study exploring the experiences and perceptions of sixteen Tibetan women who had undergone induced abortions, and five healthcare workers from hospitals in Lhasa in which abortions are carried out. Our findings in this first study of abortion in the Tibet Autonomous Region suggest that despite the availability and medical safety of abortion services, Tibetan women must deal with various social, ethical, and religious challenges related to the practice, as well as limited knowledge and availability of contraceptives.

Sixty years of change in Tibetan fertility: An assessment

Existing knowledge of Tibetan historical population development is mostly based on 'best-guess' estimates and is heavily politicized. Using census data, I reconstruct the development of Tibetan fertility in China since the 1940s, with the objective of providing an independent assessment that can be used as benchmark for future studies and debates on Tibetan demography. Following major social and economic transformations starting in the 1950s, Tibetan fertility unexpectedly increased from the late 1950s to the late 1960s. As noted in several existing studies, Tibetan fertility in China then declined swiftly from the early 1980s onwards and has now reached values close to replacement level. Focusing on the 1950-70 period, I examine factors that contributed to shaping the Tibetan fertility increase in more detail. This confirms that changes in nuptiality and disease-related infertility both played a role in pushing up fertility rates among Tibetan women in China.

Ethnically Tibetan women in Nepal with low hemoglobin concentration have better reproductive outcomes

Background and objectives: Tibetans have distinctively low hemoglobin concentrations at high altitudes compared with visitors and Andean highlanders. This study hypothesized that natural selection favors an unelevated hemoglobin concentration among Tibetans. It considered nonheritable sociocultural factors affecting reproductive success and tested the hypotheses that a higher percent of oxygen saturation of hemoglobin (indicating less stress) or lower hemoglobin concentration (indicating dampened response) associated with higher lifetime reproductive success.

Methodology: We sampled 1006 post-reproductive ethnically Tibetan women residing at 3000–4100 m in Nepal. We collected reproductive histories by interviews in native dialects and noninvasive physiological measurements. Regression analyses selected influential covariates of measures of reproductive success: the numbers of pregnancies, live births and children surviving to age 15.

Results: Taking factors such as marriage status, age of first birth and access to health care into account, we found a higher percent of oxygen saturation associated weakly and an unelevated hemoglobin concentration associated strongly with better reproductive success. Women who lost all their pregnancies or all their live births had hemoglobin concentrations significantly higher than the sample mean. Elevated hemoglobin concentration associated with a lower probability a pregnancy progressed to a live birth.

Conclusions and implications: These findings are consistent with the hypothesis that unelevated hemoglobin concentration is an adaptation shaped by natural selection resulting in the relatively low hemoglobin concentration of Tibetans compared with visitors and Andean highlanders.