Ganmaa, Davaasambuu

Товч нэр

Ganmaa, Davaasambuu

Бүтэн нэр

Ganmaa Davaasambuu

Латин нэр

Ganmaa Davaasambuu

Албан тушаал

Судлаач

Харьяалал

Анагаахын Шинжлэх Ухааны Үндэсний Их Сургууль

ORCID

0000-0003-3388-8475

Now showing 1 - 10 of 10

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Breast cancer incidence in Mongolia
(Springer Science and Business Media LLC, 2012-07)
Troisi, Rebecca
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Altantsetseg, Dalkhjav
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Davaasambuu, Ganmaa
;
Rich-Edwards, Janet
;
Tretli, Steinar
Scopus© Citations 30
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Vitamin D supplementation and growth in urban Mongol school children: Results from two randomized clinical trials
(Public Library of Science (PLoS), 2017)
Ganmaa, Davaasambuu
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Stuart, Jennifer J
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Sumberzul, Nyamjav
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Ninjin, Boldbaatar
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Giovannucci, Edward
BACKGROUND: Symptomatic vitamin D deficiency is associated with slowed growth in children. It is unknown whether vitamin D repletion in children with asymptomatic serum vitamin D deficiency can restore normal growth. OBJECTIVE: We tested the impact of vitamin D-supplementation on serum concentrations of 25-hydroxyvitamin D [25(OH)D] and short-term growth in Mongol children, with very low serum vitamin D levels in winter. DESIGN: We conducted two randomized, double-blind, placebo-controlled trials in urban school age children without clinical signs of rickets. The Supplementation Study was a 6-month intervention with an 800 IU vitamin D3 supplement daily, compared with placebo, in 113 children aged 12-15 years. A second study, the Fortification Study, was a 7-week intervention with 710 ml of whole milk fortified with 300 IU vitamin D3 daily, compared with unfortified milk, in 235 children aged 9-11 years. RESULTS: At winter baseline, children had low vitamin D levels, with a mean (±SD) serum 25-hydroxyvitamin D [25(OH)D] concentration of 7.3 (±3.9) ng/ml in the Supplementation Study and 7.5 (±3.8) ng/ml in the Fortification Study. The serum levels increased in both vitamin D groups-by 19.8 (±5.1) ng/ml in the Supplementation Study, and 19.7 (±6.1) ng/ml in the Fortification Study. Multivariable analysis showed a 0.9 (±0.3 SE) cm greater increase in height in the vitamin-D treated children, compared to placebo treated children, in the 6-month Supplementation Study (p = 0.003). Although the children in the 7-week Fortification Study intervention arm grew 0.2 (±0.1) cm more, on average, than placebo children this difference was not statistically significant (p = 0.2). There were no significant effects of vitamin D supplements on differences in changes in weight or body mass index in either trial. For the Fortification Study, girls gained more weight than boys while taking vitamin D 3 (p-value for interaction = 0.03), but sex was not an effect modifier of the relationship between vitamin D3 and change in either height or BMI in either trial. CONCLUSIONS: Correcting vitamin D deficiency in children with very low serum vitamin D levels using 800 IU of vitamin D3 daily for six months increased growth, at least in the short-term, whereas, in a shorter trial of 300 IU of D fortified milk daily for 7 weeks did not.
Scopus© Citations 45
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Randomized Trial of Vitamin D Supplementation and Risk of Acute Respiratory Infection in Mongolia
(American Academy of Pediatrics (AAP), 2012-09-01)
Camargo, Carlos A.
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Ganmaa, Davaasambuu
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Frazier, A. Lindsay
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Kirchberg, Franca F.
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Stuart, Jennifer J.
Scopus© Citations 256
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The role of hormones in the differences in the incidence of breast cancer between Mongolia and the United Kingdom
(Public Library of Science (PLoS), 2014)
Troisi, Rebecca
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Ganmaa, Daavasambuu
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dos Santos Silva, Isabel
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Davaalkham, Dambadarjaa
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Rosenberg, Philip S
BACKGROUND: There are striking differences in breast cancer incidence between Asian and western women. Rates vary substantially within Asia also, with Mongolia's even lower than China's. These profound differences have been speculated to be due in part to diet, mediated by circulating hormone concentrations. METHODS: Sex steroid hormone concentrations were measured in women living in Ulaanbaatar, Mongolia and the United Kingdom (U.K.). Diet was obtained by interview and national survey data. Mean hormone differences were compared by country, and systematic variation by number of days since last menstrual period was modeled and adjusted for age and parity; difference in overall area under the curves was assessed. FINDINGS: The diet in Mongolia was higher in meat and dairy than in the U.K. Mean testosterone concentrations were 18.5% lower (p<0.0001) while estradiol concentrations were 19.1% higher (p = 0.02) in Mongolian than British women, adjusted for age and parity. Progesterone was almost 50% higher in Mongolian women (p = 0.04), particularly during the follicular phase and early luteal surge. Hormone concentrations generally were similar in Mongolian women born in Ulaanbaatar compared with those born in rural areas, although there was a decreasing progesterone trend by degree of westernization (rural Mongolia; urban Mongolia; U.K.). Mean hormone differences were similar when restricted to parous women, and with further adjustment for body mass index, height, and smoking status. INTERPRETATION: These data augment accumulating evidence that circulating estrogens are unlikely to explain reduced breast cancer rates in Asia compared with the west, and suggest casting a wider net with respect to biomarkers. Lower testosterone and higher progesterone in Mongolian women raise the possibility that these hormones may be important to consider. In addition, the almost exclusive dietary reliance of Mongolians on meat and dairy argues against beneficial effects of a low-fat diet on circulating hormones explaining international breast cancer differences.
Scopus© Citations 14
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Prevalence and Determinants of QuantiFERON-Diagnosed Tuberculosis Infection in 9810 Mongolian Schoolchildren
(Oxford University Press, 2018-11-26)
Davaasambuu Ganmaa
;
Polyna Khudyakov
;
Uyanga Buyanjargal
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Badamtsetseg Jargalsaikhan
;
Delgerekh Baigal
BACKGROUND: There is controversy regarding the potential influence of vitamin D deficiency, exposure to environmental tobacco smoke, BCG vaccination, season, and body habitus on susceptibility to Mycobacterium tuberculosis (MTB) infection. METHODS: We conducted a cross-sectional analysis to identify determinants of a positive QuantiFERON-TB Gold (QFT) assay result in children aged 6-13 years attending 18 schools in Ulaanbaatar, Mongolia. Data relating to potential risk factors for MTB infection were collected by questionnaire, physical examination, and determination of serum 25-hydroxyvitamin D (25[OH]D) concentrations. Risk ratios (RRs) were calculated with adjustment for potential confounders, and population attributable fractions (PAFs) were calculated for modifiable risk factors identified. RESULTS: Nine hundred forty-six of 9810 (9.6%) participants had a positive QFT result. QFT positivity was independently associated with household exposure to pulmonary tuberculosis (adjusted RR [aRR], 4.75 [95% confidence interval {CI}, 4.13-5.46, P < .001]; PAF, 13.1% [95% CI, 11.1%-15.0%]), vitamin D deficiency (aRR, 1.23 [95% CI, 1.08-1.40], P = .002; PAF, 5.7% [95% CI, 1.9%-9.3%]), exposure to environmental tobacco smoke (1 indoor smoker, aRR, 1.19 [95% CI, 1.04-1.35]; ≥2 indoor smokers, aRR, 1.30 [95% CI, 1.02-1.64]; P for trend = .006; PAF, 7.2% [95% CI, 2.2%-12.0%]), and increasing age (aRR per additional year, 1.14 [95% CI, 1.10-1.19], P < .001). No statistically significant independent association was seen for presence of a BCG scar, season of sampling, or body mass index. CONCLUSIONS: Vitamin D deficiency and exposure to environmental tobacco smoke are potentially modifiable risk factors for MTB infection.
Scopus© Citations 35
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Risk factors for active tuberculosis in 938 QuantiFERON-positive schoolchildren in Mongolia: a community-based cross-sectional study
(BioMed Central, 2019-06-17)
Davaasambuu Ganmaa
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Polyna Khudyakov
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Uyanga Buyanjargal
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Delgerekh Baigal
;
Munkhzul Baatar
BACKGROUND: There is controversy regarding the relative influence of 'exogenous' versus 'endogenous' factors on the risk of progression from latent tuberculosis infection to active tuberculosis (TB) disease in children. METHODS: We conducted a cross-sectional analysis to identify risk factors for active tuberculosis in QuantiFERON®-TB Gold (QFT-G)-positive children aged 6-13 years attending 18 schools in Ulaanbaatar, Mongolia. Children underwent clinical and radiological screening for active tuberculosis, and data relating to potential risk factors for disease progression were collected by questionnaire and determination of serum 25-hydroxyvitamin D (25[OH]D) concentrations. Risk ratios were calculated using generalized estimating equations with adjustment for potential confounders. RESULTS: 129/938 (13.8%) QFT-positive children were diagnosed with active tuberculosis. Risk of active tuberculosis was independently associated with household exposure to pulmonary TB (adjusted risk ratio [aRR] 2.40, 95% CI 1.74 to 3.30, P < 0.001), month of sampling (adjusted risk ratio [aRR] for March-May vs. June-November 3.31, 95% CI 1.63 to 6.74, P < 0.001; aRR for December-February vs. June-November 2.53, 95% CI 1.23 to 5.19, P = 0.01) and active smoking by the child (aRR 5.23, 95% CI 2.70 to 10.12, P < 0.001). No statistically significant independent association was seen for age, sex, socio-economic factors, presence of a Bacillus Calmette-Guérin (BCG) scar, tobacco exposure or vitamin D status. CONCLUSIONS: Household exposure to active TB, winter or spring season and active smoking were independently associated with risk of active tuberculosis in QFT-positive children. Our findings highlight the potentially high yield of screening child household contacts of infectious index cases for active tuberculosis in low- and middle-income countries.
Scopus© Citations 14
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Associations of Breast Cancer Risk Factors with Premenopausal Sex Hormones in Women with Very Low Breast Cancer Risk
(MDPI AG, 2016-10)
Houghton, Lauren C
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Ganmaa, Davaasambuu
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Rosenberg, Philip S
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Davaalkham, Dambadarjaa
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Stanczyk, Frank Z
Breast cancer incidence rates are low but rising in urban Mongolia. We collected reproductive and lifestyle factor information and measured anthropometrics and serum sex steroid concentrations among 314 premenopausal women living in Ulaanbaatar, Mongolia. Mean differences in hormone concentrations by these factors were calculated using age-adjusted quadratic regression splines. Estrone and estradiol in college-educated women were, respectively, 18.2% (p = 0.03) and 23.6% (p = 0.03) lower than in high-school-educated women. Progesterone concentrations appeared 55.8% lower (p = 0.10) in women residing in modern housing compared with women living in traditional housing (gers), although this finding was not statistically significant. Testosterone concentrations were positively associated with adiposity and central fat distribution % difference for highest vs. lowest quarter for body mass index (17.1% (p = 0.001)) and waist-to-height ratio (15.1% (p = 0.005)). Estrogens were higher in the follicular phase of women who breastfed each child for shorter durations. A distinct hormonal profile was associated with an urban lifestyle in premenopausal, Mongol women. In particular, heavier, more-educated women living in urban dwellings had higher testosterone and lower estrogen and progesterone levels. Higher breast cancer incidence in urban compared with rural women suggest that the hormonal profile associated with a more traditional lifestyle may be protective among Mongol women.
Scopus© Citations 12
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Vitamin D, tuberculin skin test conversion, and latent tuberculosis in Mongolian school-age children: a randomized, double-blind, placebo-controlled feasibility trial
(Elsevier BV, 2012-08)
Ganmaa, Davaasambuu
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Giovannucci, Edward
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Bloom, Barry R
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Fawzi, Wafaie
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Burr, Winthrop
Scopus© Citations 92
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Vitamin D deficiency in reproductive age Mongolian women: a cross sectional study
(Elsevier BV, 2014-01)
Ganmaa, Davaasambuu
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Holick, Michael F
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Rich-Edwards, Janet W
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Frazier, Lindsay A
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Davaalkham, Dambadarjaa
Vitamin D production is critical not only for rickets prevention but for its role in several chronic diseases of adulthood. Maternal vitamin D status also has consequences for the developing fetus. This study assessed the prevalence of vitamin D deficiency (serum 25-hydroxyvitamin D [25(OH)D]<20ng/ml) and insufficiency [25(OH)D=20-29ng/ml] in spring, among reproductive age Mongolian women. Blood was drawn in March and April, 2009 from 420 Mongolian women, 18-44 years of age. Serum 25(OH)D concentrations were measured, anthropometric measurements were performed and information was collected by interview on lifestyle, dietary and reproductive factors. Logarithm-transformed 25(OH)D levels were compared across risk factor categories by analysis of variance. Linear regression analysis was used to assess the independent associations of factors with vitamin D status. Cutaneous vitamin D3 synthesis was assessed between December and July using a standard 7-dehydrocholesterol ampoule model. The vast majority of women 415 (98.8%) had serum 25(OH)D<20ng/ml (50nmol/l) with an additional 4 women (<1%) in the insufficient range (20-29ng/ml); only one women (0.2%) had sufficient levels (>30ng/ml or 75nmol/l). 25(OH)D concentrations were positively and independently associated with educational status and use of vitamin D supplements, but not with other demographic, lifestyle, reproductive, or anthropometric factors. 25(OH)D levels were not associated with dietary factors in this population, as there is little access to foods containing vitamin D in Mongolia. No production of previtamin D3 was observed until March and was maximally effective in April and was sustained through July. These data suggest that the prevalence of vitamin D deficiency in spring among reproductive age women in Mongolia is high. Given the lack of naturally vitamin D-rich food in the diet and limited use of vitamin D supplements, food fortification and/or supplementation with vitamin D should be considered among these women.
Scopus© Citations 24
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Randomized trial of fortified milk and supplements to raise 25-hydroxyvitamin D concentrations in schoolchildren in Mongolia
(Elsevier BV, 2011-08)
Rich-Edwards, Janet W
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Ganmaa, Davaasambuu
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Kleinman, Ken
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Nyamjav, Sumberzul
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Holick, Michael F
Scopus© Citations 47

Ganmaa, Davaasambuu

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