Investigator(s)
| Submitter |
Tshering Choden Khesar Gyalpo University of Medical Sciences of Bhutan Tshering Choden 
|
| Principal Investigator |
Tshering Choden Khesar Gyalpo University of Medical Sciences of Bhutan Tshering Choden
|
| Co-Investigator(s) |
Tshering Jamtsho Khesar Gyalpo University of Medical Sciences of Bhutan Tshering Jamtsho
|
| Co-Investigator(s) |
Tenzin Wangchuk Jigme Dorji Wangchuck National Referral Hospital Tenzin Wangchuk
|
Title(s) and abstract
| Scientific title | Association of Low Hemoglobin and Vitamin D Deficiency with Functional limitations among Rural Women of Reproductive Age in Bhutan: A Secondary Analysis of the 2023 National Health Survey |
| Public title | Hemoglobin and Vitamin D Deficiency among Rural Bhutanese Women |
| Background | Low hemoglobin and vitamin D deficiency are among the most common nutritional disorders affecting women of reproductive age globally, particularly in low- and middle-income countries (LMICs). Micronutrient deficiencies continue to represent major public health concerns worldwide, affecting nearly two billion people, with women disproportionately impacted due to increased physiological demands associated with menstruation, pregnancy, and lactation . In LMICs, approximately 30–50% of women aged 15–49 years are estimated to suffer from at least one micronutrient deficiency. Rural women frequently engage in labor-intensive agricultural work while having inadequate access to nutrient-rich foods and health services. This finding was also supported by the 5th National Health Survey (NHS) 2023, which revealed that vitamin D deficiency affects 91.4% of the Bhutanese population, with rural residents experiencing 20% higher odds of deficiency compared to urban residents. Additionally, approximately 35–40% of women of reproductive age in Bhutan may have low hemoglobin, while vitamin D deficiency may affect more than half of women living in rural areas. Low hemoglobin and Vitamin D deficiency have emerged as a major but often under-recognized public health problem which results in fatigue, weakness, decreased endurance, impaired cognitive performance, and reduced work productivity. Recent evidence further suggests a biological relationship between vitamin D deficiency and low hemoglobin. Women with co-existing low hemoglobin and vitamin D deficiency may therefore experience compounded impairments in physical functioning, mobility, and daily activities. In Bhutan, existing studies have mainly focused on the prevalence of micronutrient deficiencies, with limited evidence examining their effects on functional outcomes and daily functioning among women. Therefore, this study aims to investigate the association between low hemoglobin, vitamin D deficiency, and functional limitations among rural Bhutanese women aged 15–49 years using data from the 2023 Bhutan National Health Survey. |
| Objectives | General Objective To assess the association between low hemoglobin, vitamin D deficiency, and functional limitations among rural Bhutanese women aged 15–49 years. Specific Objectives 1.To determine the association between low hemoglobin and functional limitations among rural Bhutanese women aged 15–49 years. 2.To assess the association between vitamin D deficiency and functional limitations among rural Bhutanese women aged 15–49 years. 3.To compare physical functioning, mobility, and daily activity limitations between women with co-existing low hemoglobin and vitamin D deficiency and women without deficiencies. 4.To identify socioeconomic and geographic factors associated with poorer functional outcomes among women affected by micronutrient deficiencies. |
| Study Methods | This study will use a quantitative cross-sectional analytical study using secondary data from the 2023 Bhutan National Health Survey (NHS). The NHS uses a two-stage sampling design (rural/urban strata within each Dzongkhag/Thromde), PSU selected using probability proportional to size, and households chosen using circular systematic sampling with 12 households per PSU. The original survey included 11,626 households. This analysis will focus on rural women aged 15 to 49 with available data on functional outcome, hemoglobin, and vitamin D; records with implausible values will be excluded using predefined cut-offs. Exposure variables are vitamin D status (Sufficient/insufficient/deficient), low hemoglobin status (normal vs low), and combined deficiency categories (no deficiency; low hemoglobin only; vitamin D deficiency only; both). The primary outcome will be women with any functional limitation derived from from survey items on difficulty walking, self-care, concentrating, performing daily activities and work participation; secondary analyses will be conducted for individual domains if data are sufficient. Covariates include age, marital status, socioeconomic factors (education, occupation, household size, income); geographic variables (Dzongkhag, gewog); health conditions (hypertension, mental disorder, depression, anxiety), reproductive factors, environmental variables and lifestyle. The analyses will be conducted in R and incorporate NHS sampling weights, clustering and stratification. Descriptive statistics will be used to summarize the characteristics ( percentages and frequencies for categorical variables; mean±SD or medians/IQR for continuous variables) Bivariate data analysis will be performed using Chi-square (χ2) test for the categorical variables while multivariable regression models will then be used to estimate the adjusted association between exposures and binary variables; ordinal regression models might be utilized for ordinal outcomes. P-values < 0.05 will be considered statistically significant. |
| Expected outcomes and use of results | The study expects to find that rural Bhutanese women aged 15-49 with low hemoglobin and/or vitamin D deficiency have significantly higher odds of functional limitations, both overall and in specific domains like walking, self-care, concentration, and daily activities, compared to women without these deficiencies after controlling for demographics, socioeconomic factors, health conditions, reproductive factors, environment, and lifestyle. It is expected that women with both deficiencies will exhibit the largest negative correlations, suggesting an addictive effect. Poorer functional outcomes are also anticipated to be independently linked to socioeconomic and geographic disparities. The results will produce adjusted odds ratios and confidence intervals to identify high-risk categories and measure the independent effects of each deficiency. These results will drive the integration of micronutrient evaluation into primary care and maternity health services and promote community-based rehabilitative and functional support for rural women. Additionally, the study will support future research on micronutrients and physical functioning in women of reproductive age, influence resource allocation to underprivileged gewogs, and provide evidence for policy improvements in Bhutan's National Nutrition Strategy. |
| Keywords | Low hemoglobin, vitamin D deficiency, rural, both deficiencies |
Research Details
| Student research | No |
| Start Date | 01-Jul-2026 |
| End Date | 28-Nov-2026 |
| Key Implementing Institution | none |
| Multi-country research | No |
| Nationwide research | Yes |
| Research Domain(s) | Non-communicable diseases & Healthy Lifestyles |
| Research field(s) | Nutrition |
| Involves human subjects | Yes |
| Population-Based Survey | |
| Data Collection | Secondary data |
| Proposal reviewed by other Committee | No |