Alvina

UNIVERSA MEDICINA
Serum estradiol levels and bone mineral density
in postmenopausal women
Martiem Mawi*
ABSTRACT
Postmenopausal women are at high risk of disease, such as coronary heart disease, stroke, malignancies, dementia and osteoporosis. This is due to decreased levels of estrogen/estradiol, produced mainly in the ovaries, leading to reduced bonemineral density (BMD), which is the gold standard for diagnosis of osteoporosis.
Correspondence
The purpose of the present study was to determine the relationship between serum estradiol levels and BMD in postmenopausal women. The study, which was of cross-sectional design, involved 184 postmenopausal women meeting the inclusion criteria, viz. healthy postmenopausal women aged between 47 and Trisakti UniversityJl. Kyai Tapa No.260 Grogol 60 years having taken no hormonal medications in the previous 3 years. The subjects were assessed for anthropometric and biochemical characteristics, including BMD and serum estradiol levels. BMD was measured at the lumbarspine, right femoral neck and at the distal radius by the dual-energy X-ray absorptiometry (DXA) instrument. The mean serum estradiol concentration was7.54 ± 4.65 pg/ml, while in 49.5% of the subjects the estradiol concentrationwas ≤ 5 pg/ml. In postmenopausal women with estradiol concentrations of > 5pg/ml, a significant positive relationship was found between BMD and the T-scores for the femoral neck. Thus the higher the serum estradiol levels, the higherthe BMD values for femoral neck region. In conclusion, the results of this studypoint to estradiol levels as a major factor in determining the BMD values inpostmenopausal women.
Keywords: Postmenopausal, estradiol, bone mineral density, femoral neck
INTRODUCTION
be around 60–70 million.(1) Postmenopausalwomen are at high risk of disease, such as osteoporosis, hypertension, coronary heart concomitant increase in the numbers of the disease, and stroke.(2) The menopause is the 12- elderly, particularly postmenopausal women, month period after cessation of menstruation, in developed as well as developing countries.
while the postmenopausal is the period after menopause onwards.(1) In the postmenopausal postmenopausal women in the year 2025 will estradiol are no longer functional, leading to decreased levels of estradiol.(3,4) In the Unmodifiable risk factors for osteoporosis postmenopausal period there is degeneration are gender (women are of lesser weight and of the ovaries, resulting in cessation of have smaller bones than men), advanced age, estradiol production by these organs. The family history of osteoporosis, race (Asian and remaining sources of estradiol are the adrenals, osteoporosis than African women), body build aromatization of androstenedione.(5-7) Estradiol (thin and small women are at higher risk of is synthesized in osteoblasts and chondrocytes in osseous tissue from circulatory androgens, (anorexia, diabetes, chronic diarrhea, renal and hepatic disorders). Modifiable risk factors are dehydroepiandrosterone and androtenedione.(5) smoking, alcohol consumption, low calcium The reduction in bone mass is significantly intake, lack of exercise, underweight and use associated with decreased androgen levels in of medications (steroids, phenobarbital and perimenopausal and postmenopausal women.(8) phenytoin).(10) The objective of this study was Testosterone level is positively associated with to determine serum estradiol levels and their important role in maintaining estrogen levels formation and absorption are closelyassociated to one another. After the age of 30 Research design
years there is a gradual diminution of bone mass, which is most clearly seen in women, design in order to determine serum estradiol who experience a significant decrease in bone levels and their relationship with BMD values mass. This is associated with lowered estrogen production several years prior to the onset ofthe menopause and continues for a period of Study subjects
up to 5 years, followed by a slow decrease in The study subjects were randomly selected bone mass for the remaining life span of the postmenopausal women aged 47 up to 60 years women.(10) Osteoporosis is a condition of from four villages (kelurahan) in the Mampang Prapatan subdistrict, South Jakarta, namely the architecture up to the fracture threshold villages of Kuningan Barat, Mampang Prapatan, without clinical signs or symptoms.(12) In this absorption is increased. Bone loss occurs more menopause of more than one year, age 47 up frequently in trabecular bone, such as in the to 60 years, willing to participate in the study vertebrae, femoral neck and distal radius.(11) and sign informed consent, able to actively The rate of bone loss is 2-2.5% in the first 5 communicate, and actively mobile (requiring post-menopausal years, 39% in the age range of 70-79 years and 70% at age 80+ years.(12) hysterectomy or bilateral oophorectomy, acute infections, diabetes mellitus, diseases of the women in the US to be 14% at age 50-59 years, kidneys, lungs and liver, malignancies, and 22% at 60-69 years, 39% at age 70-79 years those consuming hormonal medications in the last 3 years. The respondents were interviewed Mawi Serum estradiol levels and bone mineral density osteopenia the BMD value is more than 1 SD center cadres, using a questionnaire that osteoporosis the BMD is 2.5 SD or more below menopause. All participating women signed an the reference mean.(16) Expressed as T-scores: normal if T-score > -1; osteopenia if -2.5 < T-score < -1; osteoporosis if T-score < -2.5.(15) Assessment of physical characteristics
(BMI). Height was measured to the nearest 0.1 Research Ethics Commission of the Medical cm with the subjects in the upright position without shoes. Body weight was determinedto the nearest 0.1 kg with the subjects wearing Data analysis
calculated as weight (kg)/ height (m)2. BMI is data, data entry was performed using Statistical classified into the following categories: Package for Social Science (SPSS) version 15for Windows. Initially a test of normality was underweight (< 18.5 kg/m2), normal (18.5-22.9 kg/m2), overweight (23.0-27.5 kg/m2), and distributed, correlation analysis was performedby calculating Spearman’s rho in order to Biochemical measurements
determine correlations between BMI and serum estradiol levels. The level of statistical significance was set at p < 0.05.
after a fast of 12-14 hours. Subsequently theserum was separated and stored at –700C until concentration (coefficient of variation = 3.2%) (31/125 = 0.25%) did not meet the inclusion was performed at Prodia Laboratories, Jakarta, biochemical testing revealed to have diabetes mellitus and 11 did not show up for laboratory determinations was 5.00 - 4300.00 pg/ml.
inclusion criteria participated in this study.
Mean age of the subjects was 53.58 ± 3.53 BMD measurements
years, with age range of 47 – 60 years. Mean BMI was 26.75 ± 4.68 kg/m2. The majority of lumbar vertebrae), the right femoral neck, and the distal left radius was determined by dual- energy X-ray absorptiometry (DXA), using a category. Mean estradiol concentration was 7.54 ± 4.65 pg/ml, while 46.5% of women were in the low estradiol category (≤ 5 pg/ml). Mean lumbar T-score was –1.63 ± 1.04, mean femoral neck T-score was –0.99 ± 0.96, and mean distal categories suggested by a WHO study group radial T-score was –1.95 ± 1.17. Mean duration in 1994, the normal category has a BMD within of menopause was 4.47 ± 2.24 years, with a 1 SD of the reference mean (young adults). In Table 1. Mean values for age, BMI, lumbar, of the femoral neck (r=0.021;p=0.042) (Table femoral and radial T-scores, estradiol level 3). Thus the higher the serum estradiol levels, and duration of menopause in postmenopausal the higher the BMD values for the femoral neck General characteristics
Mean ± SD
DISCUSSION
concentrations of < 5 pg/ml. In postmenopausal estradiol concentration was > 5 pg/ml, this study showed a significant positive relationship between estradiol levels and T-scores for the femoral neck region. Essentially similar resultswere found by Bagur et al. in postmenopausal women < 65 years of age, who had estradiollevels of > 10 pg/ml and higher BMD values inall skeletal sites examined, in comparison with women whose estradiol levels were < 10 pg/ osteopenia was for the lumbar vertebrae (50%), ml.(5) A study involving 370 postmenopausal women aged between 55 and 85 years found a highest in the left distal radius (35.3%) (Table significant positive relationship between serum estradiol levels and BMD values for the lumbar normality showed that serum estradiol was not normally distributed. Nonparametric correlation according to Spearman rho showed a positive degeneration resulting in diminished estradiol correlation between serum estradiol and BMD Table 2. Distribution of osteopenia and osteoporosis by BMD site Osteopenia (n,%)
Osteoporosis (n,%)
Table 3. Correlation between serum estradiol and bone mineral density in postmenopausal women with estradiol concentrations of > 5 pg/ml (n=93) Lumbar spine
Femoral neck
Distal radius
Mawi Serum estradiol levels and bone mineral density osteoporosis. Extragonadal sources of estradiol postmenopausal women, the most frequently are the adrenals, adipose tissue, liver, kidney affected by osteoporosis are the trabecular and muscle, where estradiol is synthesized bones (spongious bones).(1) As is well-known, through aromatization of andrestenedione.(7) two risk factors for osteoporosis are age and homeostasis is widely recognized, and one of increased resorption of old bone in comparison its consequences is the loss of bone occurring weaken and fracture easily at the slightest function ceases.(17) Extragonadal aromatization is affected by age, gender, and body weight.
vertebrae and wrist.(20) The reduction in bone mineral mass of the radius in men occurs after the age of 60 years. However, in women bone Lack of estrogen also causes osteoporosis, loss commences around the age of 50 years, is most rapid 3 or 4 years after menopause, and menstruation is delayed, resulting in less than on average continues at a greater rate from the normal estrogen levels. One in three women age of 67 years upwards.(19,20) In approximately half of white postmenopausal women the radial particularly after the age of 50 years.
Osteoporosis may occur at age under 45 years association was found between estradiol and bone density at all body sites examined.(21) In another study, it was found that increased age was associated with decreased estradiol and age, creating a worldwide health problem, as the aged tend to suffer from bone fractures concentrations increased bone turnover, which from mild injury or even without injury. These is a risk factor for fractures.(16) Zarrabeitia et fractures increase the morbidity and mortality al. revealed a significant correlation of serum rates, and health funding, and reduce the estradiol concentration with BMD of the spine quality of life of the patients.(10,18) In the study in postmenopausal women. In addition, the investigators also found in subjects with high decreased with advancing age, whereas BMD was proportional to BMI.(19) In the present study, it is unclear whether the extremely low estradiol level (<5 pg/ml) in the majority of the respondents was caused by lack of dietary limitations. First, as this was a cross-sectional cholesterol (fat), since estrogen is synthesized community-based study, no conclusions can be in the liver and some is of dietary origin.
drawn as regards the cause-effect relationship calcium, low vitamin D and lack of exercise, longitudinal studies will be necessary to which affects bone density. It is reported that confirm our conclusions. Secondly, the women osteoporosis in Asia is intimately associated in this study were aged between 47 and 60 with low calcium and lack of vitamin D.
years, for whom no BMD data were available.
Around 35% of postmenopausal women in Asia Thirdly, no measured values of free estrogen CONCLUSIONS
Tana L. Pencegahan osteoporosis. Media LitbangKesehatan 2005;15:50-7.
Sowers MR, Jannausch M, Mc Connell D, Little R, Greendale GA, Filkelstein JS, et al. Hormone years 49.5% had serum estradiol levels of ≤ 5 predictors of bone mineral density changes during pg/ml. There was a significant correlation the menopausal transition. J Clin Endocrinol Ninghua L, Pinzhong O, Harmin Z, Dingzhuo Y,Pinru Z. Prevalence rate of osteoporosis in the mid-aged and elderly in selected parts of China.
Clind Med J 2002;115:773-5.
ACKNOWLEDGEMENTS
World Health Organization. Appropiate bodymass index for Asian populations and its implications for policy and intervention strategies.
The Lancet 2004;363:157-63.
to the Medical Faculty, Trisakti University, for the funding of this study. And also thanks the fracture risk and its application to screening for respondents who were willing to participate in postmenopausal osteoporosis. WHO technical report series 843. Geneva: World HealthOrganization;1994.
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