Aromatase Inhibitors and Weight Loss in Severely Obese Men With Hypogonadism
Study Details
Study Description
Brief Summary
The investigators have preliminary data suggesting that obese patients with hypogonadotropic hypogonadism (HHG) have minimal benefit from testosterone therapy likely because of its conversion to estradiol by the abundant aromatase enzyme in the adipocytes. The increased conversion of androgens into estrogens in obese men results in a negative feedback of high estradiol levels on hypothalamus and pituitary, inhibiting the production of gonadotropin-releasing hormone (GnRH), luteinizing hormone (LH) and follicle stimulating hormone (FSH) and, as a consequence, of testosterone by the testis. Testosterone administration could increase estradiol production, further promoting the inhibitory feedback to the hypothalamic-pituitary-gonadal axis. Although weight loss from lifestyle modification has been shown to reduce estradiol and increase testosterone levels, the effect is at best modest and weight regain results in recurrence of hypogonadism. The use of aromatase inhibitors, in combination with weight loss, could be an effective alternative strategy due to its action at the pathophysiology of the disease.
Intervention Subjects (body mass index of ≥35, testosterone <300 ng/dl) will be randomized to the active (anastrozole) or control (placebo) group. Anastrozole 1 mg tablet / day will be self-administered with or without food, at around the same time every day (active group); placebo 1 tablet/day with or without food to take at around the same time every day (control group). The study duration will be 12 months.
Both groups will undergo lifestyle intervention consisting of diet and supervised exercise program. Target weight loss will be at least 10% of baseline body weight during the intervention. Subjects will attend weekly group behavior modification sessions which will last ~75-90 min for the first 3 months and decreased to every two weeks from 3 to 12 months. Subjects will attend supervised research center-based exercise sessions during the first 6 months followed by community fitness center-based sessions during the next 6 months for at least 2 d/wk, with recording of home-based exercises for the other 2-4 days/week.
| Condition or Disease | Intervention/Treatment | Phase |
|---|---|---|
|
Phase 4 |
Detailed Description
After age of 40, testosterone (T) production in men gradually decreases at a rate of 1.6% per year for total and to 2-3% per year for bioavailable T. This reduction in T production in men parallels the age-associated loss of muscle mass that leads to sarcopenia and impairment of function and the age-associated loss of bone mass that leads to osteopenia and fracture risk.
Hypogonadism is a condition associated with multiple symptom complex including fatigue, depressed mood, osteoporosis, gain of fat mass, loss of libido and reduced muscle strength, all of which deeply affect patient quality of life. The prevalence of hypogonadism among obese men was estimated to be as much as 40% and could as much as 50% if they are also diabetic, with levels of androgens decreasing proportionately to the degree of obesity.
In obese men, the age-related decline in T is exacerbated by the suppression of the hypothalamic-pituitary-gonadal axis by hyperestrogenemia. The high expression of aromatase enzyme in the adipose tissue enhances the conversion of androgens into estrogens which in turn exerts a negative feedback on hypothalamus and pituitary, inhibiting the production of gonadotropin-releasing hormone (GnRH), luteinizing hormone (LH) and follicle stimulating hormone (FSH) and, as a consequence, of T by the testis resulting in hypogonadotropic hypogonadism (HH). Considering the high aromatase expression in the adipose tissue, the administration of T among obese men with HHG could increase the conversion of the substrate T to estradiol (E2) and fuels the negative feedback on hypothalamus and pituitary, producing a greater suppression of GnRH and gonadotropins. Thus, men with obesity induced HHG may benefit from other treatment strategies that target the pathophysiology of the disease.
Although weight loss intervention improves hormonal and metabolic abnormalities related to obesity, the increase in T levels induced by weight loss are often lost due to weight regain, which is very frequent among patients undergoing massive weight loss. One possible approach is the use of aromatase inhibitors (AI) to stop the conversion of T to E2 thereby interrupting the vicious cycle of E2 inhibition of the hypothalamic-pituitary-gonadal axis and restoring T production to normal levels. Since weight loss remains the standard of care for obese patients, the investigators propose the following OBJECTIVES:
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To evaluate the effect of an AI plus WL (AI+WL) compared to WL alone on the changes in hormonal profile in severely obese men with HHG.
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To evaluate the effect of an AI+WL compared to WL alone on the changes in muscle strength and muscle mass, and symptoms of hypogonadism in severely obese men with HHG.
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To evaluate the effect of an AI+WL compared to WL alone on the changes in body composition and metabolic risk factors in severely obese men with HHG.
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To evaluate the effect of an AI+WL compared to WL alone on the changes in bone mineral density (BMD), bone markers, and bone quality in severely obese men with HHG.
As secondary aim, the investigators will elucidate the mechanism for the anticipated positive effects of AI+WL on obesity-associated HHG.
This is a randomized double-blind placebo-controlled study comparing the effect of weight loss + anastrozole to weight loss + placebo for 12 months on the hormonal profile and symptoms associated with hypogonadism in severely obese men with a body mass index (BMI) of more or equal to 35 kg/m2.
Study Design
Arms and Interventions
| Arm | Intervention/Treatment |
|---|---|
| Placebo Comparator: Weight loss plus placebo Participants will take a placebo every day, attend behavioral classes conducted by a dietitian, receive instruction on how to loss 10% of their body weight and undergo supervised exercise training program. |
Drug: Placebo
Participants will take a placebo tablet every day, attend behavioral classes conducted by a dietitian, receive instruction on how to loss 10% of their body weight and participate in a supervised exercise training program.
Other Names:
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| Experimental: Weight loss plus anastrozole Participants will take Anastrozole 1mg per day, attend behavioral classes conducted by a dietitian, receive instruction on how to loss 10% of their body weight and undergo supervised exercise training program. |
Drug: anastrozole (1 mg/day)
Participants will take Anastrozole 1mg per day, attend behavioral classes conducted by a dietitian, receive instruction on how to loss 10% of their body weight and participate in a supervised exercise training program.
Other Names:
|
Outcome Measures
Primary Outcome Measures
- Hormonal Profile Changes [12 months]
Assessed by changes in serum testosterone levels.
- Changes in muscle strength [12 months]
Assessed by changes in knee extension strength using a dynamometer.
- Changes in Lean mass [12 months]
Assessed by body composition tissue measurement using dual energy x-ray absorptiometry.
- Changes in total hip bone mineral density (BMD) [12 months]
Assessed by dual energy absorptiometry.
Secondary Outcome Measures
- Other gonadal hormone [12 months]
Assessed by changes in serum estradiol
- Pituitary hormone [12 months]
Assessed by changes in serum luteinizing hormone (LH)
- Pituitary hormone [12 months]
Assessed by changes in serum follicle stimulating hormone (FSH)
- Changes in thigh muscle volume [12 months]
Assessed magnetic resonance imaging of both thighs.
- Changes in symptoms of hypogonadism [12 months]
Assessed by the Androgen Deficiency in Aging Male (ADAM) questionnaire; higher scores indicating worse outcome
- Changes in symptoms of hypogonadism [12 months]
Assessed by the International Index of Erectile Function (IIEF) questionnaire; higher scores indicating better outcome
- Changes in symptoms of hypogonadism [12 months]
Assessed by the 36-Item Short-Form Health Survey (SF-36) questionnaire; scores on the physical and mental component subscales of the SF-36 range from 0 to 100, with higher scores indicating better health status
- Changes in visceral adipose tissues [12 months]
Assessed by dual energy x-ray absorptiometry
- Changes in metabolic risk factors [12 months]
Assessed by hemoglobin A1C
- Changes in metabolic risk factors [12 months]
Assessed by lipid profile
- Changes in metabolic risk factors [12 months]
Assessed by homeostasis model assessment for insulin resistance (HOMA-IR)
- Changes in volumetric bone density [12 months]
Assessed by high-resolution peripheral quantitative computer tomography
- Changes in bone quality [12 months]
Assessed by changes in finite element analysis using high-resolution peripheral quantitative computer tomography
- Changes in bone markers [12 months]
Assessed by serum C-telopeptide
- Changes in bone markers [12 months]
Assessed by serum osteocalcin
- Changes in bone markers [12 months]
Assessed by serum procollagen 1 Intact N-terminal
Eligibility Criteria
Criteria
Inclusion Criteria:
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obese men with body mass index (BMI) of ≥35 kg/m2
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age between 40 to 65 years old
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average fasting testosterone level from 2 measurements taken between 8 to 10 AM on 2 separate days of <300 ng/dl
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Luteinizing Hormone (LH) of <9.0 mIU/L
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Estradiol of ≥17 pg/ml
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Symptoms consistent with androgen deficiency as assessed by Androgen Deficiency in Aging Male (ADAM) questionnaire
Exclusion criteria:
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pituitary or hypothalamic disease,
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drugs affecting gonadal hormone levels, production and action or bone metabolism (bisphosphonates, teriparatide, denosumab, glucocorticoids, phenytoin)
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diseases affecting bone metabolism (e.g. hyperparathyroidism, untreated hyperthyroidism, osteomalacia, chronic liver disease, significant renal failure, hypercortisolism, malabsorption, immobilization, Paget's disease),
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prostate carcinoma or elevated serum prostate specific antigen (PSA)> 4 ng/ml,
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Hematocrit > 50%,
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untreated severe obstructive sleep apnea,
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Cardiopulmonary disease (e.g. recent myocardial infarction, unstable angina, stroke) or unstable disease (e.g., New York Heart Association Class III or IV congestive heart failure
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severe pulmonary disease requiring steroid pills or the use of supplemental oxygen (that would contraindicate exercise or dietary restriction)
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History of deep vein thrombosis or pulmonary embolism
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severe lower urinary tract or prostate symptoms with International Prostate Symptom Score (IPSS) above 19
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excessive alcohol or substance abuse
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unstable weight (i.e. >±2 kg) in the last 3 months
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condition that could prevent from completing the study
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screening bone mineral density (BMD) T-score of <-2.0 at the spine, femoral neck or total femur
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history of osteoporosis or fragility fracture
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Diabetes mellitus with a fasting blood glucose of >140 mg/dl, and/or Hemoglobin A1C (A1C) >8.5%.
Contacts and Locations
Locations
| Site | City | State | Country | Postal Code | |
|---|---|---|---|---|---|
| 1 | Michael E. DeBakey VAMC | Houston | Texas | United States | 77030 |
Sponsors and Collaborators
- Baylor College of Medicine
Investigators
None specified.Study Documents (Full-Text)
None provided.More Information
Publications
None provided.- H-41814