Malic enzyme gene polymorphism is associated with responsiveness in circulating parathyroid hormone after long-term calcium supplementation.

OBJECTIVE: To identify genetic variations associated with parathyroid hormone (PTH) suppression after long-term calcium supplementation. DESIGN AND PARTICIPANTS: For high throughput SNP screening, subjects consisted of 171 postmenopausal women without osteoporosis at the lumbar spine. A separate group of 19 premenpausal women were recruited for calcium absorption study. Postmenopausal women in the screening group were given 500 mg/day calcium supplementation. SETTING: Bangkok, Thailand. MEASUREMENTS: Parathyroid hormone (PTH) and bone mineral density (BMD) were measured at baseline and 2 years after calcium supplementation. High throughput single-nucleotide polymorphism (SNP) screening was performed by comparing estimated allele frequencies derived from hybridization signal intensities of pooled DNA samples on Affymetrix's 10K SNP genotyping microarrays based responsiveness in PTH after calcium supplementation. Genotyping of SNP rs1112482 in malic enzyme gene (ME1) gene, a SNP among those with highest odds ratio of being related to PTH suppression after calcium, was performed in all postmenopausal subjects in the screening group and premenopausal women in the calcium absorption study group in which fractional calcium absorption was assessed by stable isotope dilution. Data were expressed as mean +/- SEM. RESULTS: PTH significantly decreased after 2 years of calcium supplementation (4.7 ± 1.9 vs. 4.4 ± 1.6 pmol/L, P < 0.01). There was a significant increase in lumbar spine BMD (1.03 ± 0.01 vs. 1.01 ± 0.01 g/cm2, P < 0.001) but not femoral neck BMD. In 108 subjects whose PTH levels decreased after calcium, the suppression of PTH was higher in those with at least one C allele in rs1112482 of ME1 gene (-26.3 ± 2.1 vs. -16.9 ± 1.4%, P < 0.001). Fractional calcium absorption also tends to the higher in subjects in the calcium absorption study group with at least one C allele (n = 6) compared to those without the C allele (n = 13) (58.0 ± 4.9 vs. 49.3 ± 2.8%, P = 0.054). CONCLUSION: Cytosolic malic enzyme 1 gene polymorphism is associated with the degree of suppression of parathyroid hormone after long-term calcium supplementation. The effect is probably mediated through an increase in intestinal calcium absorption.

Sexual maturation in Thai boys.

BACKGROUND: A worldwide secular trend towards earlier onset of puberty in girls has been noted during recent years. However, the data on sexual maturation of boys are relatively scarce and normative data of sexual maturation in Thai boys are still lacking. AIM: To determine the age of secondary sexual maturation in normal Thai boys. METHODS: Three hundred healthy urban boys aged 9-18 years were recruited during January 1997 to December 1999. Genital and pubic hair maturity staging was determined using the method of Marshall and Tanner. Testicular size was assessed by Prader orchidometer. Probit analysis was used to analyze the onset of puberty (gonadarche) and pubarche. RESULTS: Median (range) ages of the onset of puberty and pubarche were 10.8 (9.5-12) and 12.4 (10.9-13.9) years, respectively. CONCLUSION: The age of onset of genital development in boys living in Bangkok seems to be slightly earlier than that of boys in other countries. However, the onset of pubic hair development is comparable.

Dietary intake of spices and herbs in habitual northeast thai diets.

Spices and herbs are rich in polyphenols and widely used in habitual diets in the tropical regions. To elucidate their effects on human health, intake of the portion of spices and herbs from habitual diets should be determined. Consumption patterns were determined from 24-hour records or recalls of 181 men and 370 women in Khonkaen and Ubon Ratchathani provinces, representing upper and lower northeast Thailand. There was a slight variation in dishes, but twelve spices/herbs were commonly used in the two areas. The amounts of spices/ herbs in the four most common dishes (Somtum, Jaew, Pon and Kang-Nor-Mai) were estimated by weighing ingredients before and after cooking. The average amount of spices/herbs consumed was 4.9, 26.1, 14 and 11 g/meal, contributing 36.6, 43.1, 20.6 and 29.8 mg polyphenols/meal for Somtum, Jaew, Pon and Kang- Nor-Mai, respectively. Chili was common in all recipes, with an average amount of 8.3-27.5 mg polyphenols/meal. In conclusion, habitual northeast Thai diets contain several spices/herbs and a substantial amount of polyphenols was commonly consumed.

Calcium absorption from commonly consumed vegetables in healthy Thai women.

The absorbability of calcium from ivy gourd, a green leafy vegetable (Coccinia grandix Voigt.) and winged bean young pods (Psophocarpus tetragonolobus [L] DC) were measured in 19 healthy adult women aged 20 to 45 y, in a 3-way, randomized-order, crossover design with an average calcium load of 100 mg and milk as the referent. The test meals were extrinsically labeled with 44Ca and given with rice as breakfast after an overnight fast. Absorption of calcium was determined on a blood sample drawn 5 h after ingestion of the test meal. Fractional calcium absorption (X+/- SD) was 0.391 +/- 0.128 from winged beans, 0.476 +/- 0.109 from ivy gourd, and 0.552 +/- 0.119 from milk. The difference in fractional calcium absorption for these 2 vegetables was significant (P < 0.05) and the fractional calcium absorption from these 2 vegetables were both significantly lower than from milk. The difference was partly accounted for by the phytate, oxalate, and dietary fiber content of the vegetables. However, calcium bioavailability of these 2 vegetables, commonly consumed among Thais, was relatively good compared to milk (71% to 86% of milk) and could be generally recommended to the public as calcium sources other than milk and Brassica vegetables.

Effects of physical activity and dietary calcium intake on bone mineral density and osteoporosis risk in a rural Thai population.

The objective of the study was to determine the effects of modifiable risk factors on bone mineral density in postmenopausal Thai women. Dietary calcium intake (g/day), energy expenditure (kcal/day), and sunlight exposure (h/day) were assessed in 129 rural Thai women aged 63 years (range 50 to 84 years). Bone mineral density (BMD) at the femoral neck, lumbar spine, and distal radius were measured by dual-energy X-ray absorptiometry (DXA). The average dietary calcium intake was 236 +/- 188 g/day (mean +/- SD), while the energy expenditure was 2,118 +/- 656 kcal/day with 1.1 +/- 1.7 h of sunlight exposure. In multiple linear regression analysis, dietary calcium intake, energy expenditure, and years since menopause were significant and independent predictors of BMD at various sites. The three factors together accounted for between 35% and 45% of the variance of BMD. The prevalence of osteoporosis (defined as BMD T-scores < or =-2.5) was 33% at the femoral neck, 42% at the lumbar spine, and 35% at the distal radius. The risk of osteoporosis was higher in women with lower dietary calcium intake (< or =138 mg/day; prevalence rate ratio [PRR], 1.4; 95% confidence interval [CI], 1.0 to 1.9), lower energy expenditure (< or =1,682 kcal; PRR, 1.7; 95% CI, 1.2 to 2.3), and greater years since menopause (> or =6 years; PRR, 2.6; 95% CI, 1.2 to 5.8). The population attributable risk fraction of osteoporosis risk due to the three factors was 70%. These results suggest that in the Thai population, low dietary calcium intake and low physical activity together with advancing years since menopause were independent risk factors for low BMD.

Different mechanism of bone loss in ageing women and men in Khon Kaen Province.

UNLABELLED: The changes of vitamin D status and biochemical markers of bone turnover have been reported with aging. In this study we determined age-related levels of vitamin D and biochemical markers of bone turnover in the general adult population between the ages of 20 and 84 years who were living in Khon Kaen province in northeastern Thailand. Serum 25 hydroxyvitamin D was determined as an indicator of vitamin D status. Serum total alkaline phosphatase and N-terminal mid fragment osteocalcin were measured as biochemical markers of bone formation and serum C-terminal fragment of type I collagen was measured as a marker of bone resorption. The levels of serum 25 hydroxyvitamin D were high in the Khon Kaen population. Men had higher levels of 25 hydroxyvitamin D than did women. However, there were no changes with age in either sex. In women, all biochemical markers of bone turnover increased with age after the fourth decade. The sharp increase was observed in the sixth decade which was around the menopausal age. In contrast, in men all biochemical markers of bone turnover except serum total alkaline phosphatase had a tendency to decrease with age. CONCLUSION: There was no evidence of vitamin D deficiency in a Khon Kaen population. In addition, serum vitamin D levels did not decline with ageing. Women and men showed different changes of biochemical markers of bone turnover with ageing indicating gender difference in the pathogenesis of osteoporosis.

Elevated serum cholesterol levels in Bangkok children and adolescents.

Hypercholesterolemia is a major cardiovascular risk factor. This study aimed to assess serum total cholesterol (TC) levels of children and adolescents living in Bangkok, Thailand. During 1995-1997, nonfasting blood samples were obtained from 570 healthy school children and adolescents aged 9-18 years. The mean TC levels ranged from 143-180 mg/dl in males and from 145-202 mg/dl in females. The prevalences of hypercholesterolemia (TC > or = 200 mg/dl) were 12.2 per cent and 20.3 per cent in males and females, respectively. Twenty-eight per cent of males and 26.9 per cent of females had borderline values (TC 170-199 mg/dl). TC inversely correlated with age (r = -0.16, P < 0.01) in males. The findings indicate that notable percentage of these children had elevated cholesterol levels and warrant additional study concerning risk factors and tracking of lipoprotein levels from childhood into adulthood.

Lymphocyte responsiveness of children supplemented with vitamin A and zinc.

We sought to determine the effect of supplementation with zinc, vitamin A, or a combination of the two on proliferation of T lymphocytes to concanavalin A (ConA), tetanus toxoid (TT), or tuberculin (PPD) of children living in a region endemic for suboptimal vitamin A and zinc intake. The children (n = 140, aged 6-13 y) were randomly assigned and supplemented with either zinc (25 mg/d), vitamin A (1500 mg RE/d), zinc + vitamin A, or placebo for 6 mo. After a baseline blood collection, subjects were boosted with diphtheria-tetanus antigen. Proliferative responsiveness of T lymphocytes to ConA and TT in each treatment group (n = 35) was not different at baseline or postsupplementation. Children supplemented with zinc + vitamin A tended to show higher proliferative responsiveness of T lymphocytes to PPD than did those treated with placebo (P = 0.08). This tendency was observed in females but not in males. Increased zinc and vitamin A intake could result in health benefits for children living in regions endemic for suboptimal micronutrient nutriture.

Effect of vitamin A and zinc supplementation on the nutriture of children in Northeast Thailand.

Previous surveys suggested that young children in Northeast Thailand may benefit from vitamin A and/or zinc supplementation. One hundred thirty-three children aged 6-13 y with marginal plasma retinol (less than 1.05 mumol/L) and Zn (less than 12.2 mumol/L) concentrations participated in a double-blind study. They were randomly assigned and supplemented with either zinc (25 mg/d), vitamin A (1500 RE/d), zinc plus vitamin A, or placebo for 6 mo. Biochemical indices of vitamin A (plasma vitamin A, retinol-binding protein) and zinc status (plasma zinc, alkaline phosphatase) increased significantly. The children had adequate liver stores of vitamin A (relative dose response less than 20%). Zinc supplementation resulted in an improvement in vision restoration time (VRT) in dim light (dark adaptometry). Vitamin A and zinc synergistically normalized conjunctival epithelium as measured by conjunctival impression cytology (CIC). Both functional indices, VRT and CIC, showed significant correlations with plasma zinc and vitamin A, respectively. The data suggest that functional improvements in populations with suboptimal vitamin A and zinc nutriture can be accomplished by supplementation with less than two times the recommended dietary allowance of these nutrients.