Consensus report of the coalition for clinical research-self-monitoring of blood glucose

The Coalition for Clinical Research-Self-Monitoring of Blood Glucose Scientific Board, a group of nine academic clinicians and scientists from the United States and Europe, convened in San Francisco, California, on June 11-12, 2008, to discuss the appropriate uses of self-monitoring of blood glucose (SMBG) and the measures necessary to accurately assess the potential benefit of this practice in noninsulin-treated type 2 diabetes mellitus (T2DM). Thirteen consultants from the United States, Europe, and Canada from academia, practice, and government also participated and contributed based on their fields of expertise. These experts represent a range of disciplines that include adult endocrinology, pediatric endocrinology, health education, mathematics, statistics, psychology, nutrition, exercise physiology, and nursing. This coalition was organized by Diabetes Technology Management, Inc. Among the participants, there was consensus that: protocols assessing the performance of SMBG in noninsulin treated T2DM must provide the SMBG intervention subjects with blood glucose (BG) goals and instructions on how to respond to BG data in randomized controlled trials (RCTs);intervention subjects in clinical trials of SMBG-driven interventions must aggressively titrate their therapeutic responses or lifestyle changes in response to hyperglycemia;control subjects in clinical trials of SMBG must be isolated from SMBG-driven interventions and not be contaminated by physician experience with study subjects receiving a SMBG intervention;the best endpoints to measure in a clinical trial of SMBG in T2DM include delta Hemoglobin A1c levels, hyperglycemic events, hypoglycemic events, time to titrate noninsulin therapy to a maximum necessary dosage, and quality of life indices;either individual randomization or cluster randomization may be appropriate methods for separating control subjects from SMBG intervention subjects, provided that precautions are taken to avoid bias and that the sample size is adequate;treatment algorithms for assessing SMBG in T2DM may include a dietary, exercise, and/or medication intervention, which are all titratable according to the SMBG values;the medical literature contains very little information about the performance of SMBG in T2DM from RCTs in which treatment algorithms were used for dysglycemic values; and research on the performance of SMBG in T2DM based on sound scientific principles and clinical practices is needed at this time.

A case for clarity, consistency, and helpfulness: state-of-the-art clinical practice guidelines in endocrinology using the grading of recommendations, assessment, development, and evaluation system

CONTEXT

The Endocrine Society, and a growing number of other organizations, have adopted the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system to develop clinical practice guidelines and grade the strength of recommendations and the quality of the evidence. Despite the use of GRADE in several of The Endocrine Society's clinical practice guidelines, endocrinologists have not had access to a context-specific discussion of this system and its merits.

EVIDENCE ACQUISITION

The authors are involved in the development of the GRADE standard and its application to The Endocrine Society clinical practice guidelines. Examples were extracted from these guidelines to illustrate how this grading system enhances the quality of practice guidelines.

EVIDENCE SYNTHESIS

We summarized and described the components of the GRADE system, and discussed the features of GRADE that help bring clarity and consistency to guideline documents, making them more helpful to practicing clinicians and their patients with endocrine disorders.

CONCLUSIONS

GRADE describes the quality of the evidence using four levels: very low, low, moderate, and high quality. Recommendations can be either strong ("we recommend") or weak ("we suggest"), and this strength reflects the confidence that guideline panel members have that patients who receive recommended care will be better off. The separation of the quality of the evidence from the strength of the recommendation recognizes the role that values and preferences, as well as clinical and social circumstances, play in formulating practice recommendations.

A randomized trial of the effects of rosiglitazone and metformin on inflammation and subclinical atherosclerosis in patients with type 2 diabetes

BACKGROUND

Metformin and rosiglitazone both improve glycemic control in type 2 diabetes mellitus, however may possess different anti-inflammatory and anti-atherosclerotic properties. We investigated the effects of these medications on high-sensitivity C-reactive protein (hsCRP) and carotid artery intima-media thickness (CIMT) to determine their relative potential to reduce cardiovascular risk independent of their antihyperglycemic actions.

METHODS

Ninety-two subjects with suboptimally controlled diabetes mellitus (hemoglobin A1c [HbA1c] >7.0%) were assigned to therapy with either rosiglitazone 4 mg once daily or metformin 850 mg twice daily for 24 weeks. The primary end point was the change in hsCRP after 24 weeks. The change in CIMT was prespecified as a secondary end point.

RESULTS

Metformin and rosiglitazone treatment led to similar significant improvements in glycemic control (HbA1c -1.08% in the rosiglitazone group and -1.18% in the metformin group, P = nonsignificant). High-sensitivity C-reactive protein levels decreased by an average of 68% in the rosiglitazone group (5.99 +/- 0.88 to 1.91 +/- 0.28 mg/L, P < .001), compared with a nonsignificant 4% reduction in hsCRP with metformin (5.69 +/- 0.83 to 5.46 +/- 0.92 mg/L; P = nonsignificant). Maximal CIMT progressed in the metformin group (+0.084 +/- 0.038 mm), whereas regression of maximal CIMT was observed in the rosiglitazone group (-0.037 +/- 0.031 mm; P = .02 for the between group comparison). Similar changes were observed for mean CIMT. The change in hsCRP and maximal CIMT were related in a multivariable model controlling for changes in HbA1c and lipid parameters (r = .31; P = .01).

CONCLUSIONS

Rosiglitazone, compared to metformin, induced a prompt and profound reduction in hsCRP levels independent of its effect on glycemia. This change was associated with regression of CIMT after 24 weeks.

The sensitivity and specificity of nonmydriatic digital stereoscopic retinal imaging in detecting diabetic retinopathy

OBJECTIVE

The objective of this study was to determine the sensitivity and specificity of Joslin Vision Network nonmydriatic digital stereoscopic retinal imaging (NMDSRI) as a screening tool in detecting diabetic retinopathy.

RESEARCH DESIGN AND METHODS

We reviewed the records of 244 patients with diabetes who had a dilated funduscopic examination (DFE) and NMDSRI done within 1 year of each other at four locations in the metropolitan Washington, DC, area. The images were transmitted through a local area network to a central reading location where they were graded by a single retinal specialist.

RESULTS

Images of 482 eyes from 243 patients were included in the study. Four images did not transmit, and 35% of the images were not gradable. Of the remaining 311 eyes, there was 86% agreement in the grading between NMDSRI and DFE: 227 eyes with no diabetic retinopathy and 40 eyes with diabetic retinopathy. In 46 eyes (15%) there was a disagreement between gradings made by the two techniques. NMDSRI detected diabetic retinopathy in 35 eyes reported as normal by DFE, and in the remaining 11 eyes, the DFE grade was one grade higher than the NMDSRI grade. Adjudicated nonconcordant examinations were within one grade. In the 76 eyes with diabetic retinopathy, retinal thickness could not be assessed in 17 (21%) eyes. When the NMDSRI result was gradable, the overall sensitivity of NMDSRI was 98% and the specificity was 100% for retinopathy within one grade of the DFE. In the limited number of eyes that had diabetic retinopathy with macular edema (six), agreement with the clinical examination was 100%.

CONCLUSIONS

NMDSRI is a sensitive and specific method for the screening and diagnosis of diabetic retinopathy, which may help improve compliance with the standards of eye care for patients with diabetes.

Incidence and clinical significance of elevated macroprolactin levels in patients with hyperprolactinemia

OBJECTIVE

To determine the prevalence and clinical characteristics of patients with macroprolactinemia in an endocrinology practice at a tertiary care military medical center in the United States.

METHODS

We reviewed the medical records of 40 patients who had been referred for evaluation of hyper-prolactinemia between June 2003 and August 2004 in whom macroprolactin had been measured.

RESULTS

Of the 40 patients, 18 (9 men and 9 women) (45%) had an elevated macroprolactin level (mean, 75% of the total prolactin). The demographic characteristics of these patients were similar to those of patients with elevated monomeric prolactin. Most of the men with macro-prolactinemia (78%) had erectile dysfunction as the presenting complaint, whereas the most frequent symptom in women was menstrual irregularities (56%). Fifty percent of patients had no identifiable cause for their presenting complaint other than macroprolactinemia. Of the 18 patients with macroprolactinemia, 16 underwent magnetic resonance imaging (MRI) of the pituitary, of whom 56% had normal findings. Of the patients with abnormal MRI findings, 57% had a microadenoma, and 43% had either an atrophic anterior lobe or a prominent hypophysis. No significant relationship was detected between MRI findings or symptoms and the presence of elevated macroprolactin levels. Approximately 40% of patients in the macroprolactin group were treated with a dopamine agonist, 28% of whom had normalization of the total prolactin level.

CONCLUSION

Although macroprolactin is commonly found in patients with hyperprolactinemia, neither symptoms nor MRI findings are useful in predicting its presence. Patients with macroprolactinemia often have symptoms similar to those in patients with elevation in monomeric prolactin. The clinical significance of macro-prolactinemia remains uncertain.

Glycemic control with regular versus lispro insulin sliding scales in hospitalized Type 2 diabetics

PURPOSE

The aim of this study was to compare glycemic control with either regular or lispro insulin sliding scales in hospitalized Type 2 diabetics who were not using insulin as outpatients.

METHODS

Forty-three patients with Type 2 diabetes, who were taking oral agents only, were admitted to a medical inpatient service and randomized to receive either regular or lispro insulin sliding scale. Oral agents for diabetes were held upon admission and patients were followed throughout their hospital stay.

RESULTS

There was no significant difference (P>.05) between the average finger-stick blood glucose (FSBG) in the regular insulin group (157.78+/-40.16 mg/dl) and the lispro insulin group (152.04+/-27.71 mg/dl). No significant difference was found between the daily dose of insulin (regular, 5.83+/-5.01 units; lispro, 4.27+/-3.40 units), total amount of insulin used during hospitalization (regular, 11.87+/-10.78 units; lispro, 12.77+/-14.39 units), glucose excursion (regular, 110.13+/-25.86 mg/dl; lispro, 106.77+/-52.65 mg/dl), or length of hospital stay (regular, 2.33+/-1.23 days; lispro, 2.69+/-1.59 days).

CONCLUSION

No significant difference in glycemic control was found in hospitalized Type 2 diabetic patients who received either regular or lispro insulin sliding scales. Both insulin sliding scales used in this study are inadequate to achieve current recommended glycemic targets in this patient population, when used as the only inpatient treatment for diabetes.

Thyrotropin suppression by metformin

CONTEXT

Drug-drug interactions are common but often are discovered only long after initial drug release. Metformin has been available in the United States for 9 yr and elsewhere for many years, but as of yet there are no reports that the drug modifies thyroid hormone economy.

OBJECTIVE

The objective of the study was to describe the clinical and biochemical findings of four patients with chronic hypothyroidism, previously euthyroid on fixed doses of L-T4 for several years, in whom the metformin was initiated.

DESIGN

This was a retrospective review.

SETTING

The study was conducted at a tertiary care military hospital providing care to active-duty soldiers, sailors, and marines, retirees of the armed forces, and their eligible dependents.

PARTICIPANTS

Four patients with chronic hypothyroidism who were placed on metformin participated in the study. INTERVENTION, MAIN OUTCOME MEASURE: Serum TSH, free T4, and free T3 levels were measured during metformin treatment.

RESULTS

Initiation of treatment with metformin (three for diabetes mellitus and one for nonalcoholic steatohepatitis) caused suppression of TSH to subnormal levels without clinical symptoms of hyperthyroidism in any patients. There was no change in free T4 or free T3 in patient 1.

CONCLUSIONS

No other potential causes of TSH suppression, including medication changes or interference in the TSH assay, could be identified. The mechanism of the fall in serum TSH in these four patients is unclear at this time. Should these findings be confirmed in larger prospective studies, metformin's ability to suppress TSH without causing clinical or chemical hyperthyroidism might render this drug a useful adjunct to the treatment of patients with thyroid cancer.

A Modeled Economic Analysis of a Digital Teleophthalmology System As Used by Three Federal Healthcare Agencies for Detecting Proliferative Diabetic Retinopathy

The objective of this study was to compare, using a 12-month time frame, the cost-effectiveness of a non-mydriatic digital tele-ophthalmology system (Joslin Vision Network) versus traditional clinic-based ophthalmoscopy examinations with pupil dilation to detect proliferative diabetic retinopathy and its consequences. Decision analysis techniques, including Monte Carlo simulation, were used to model the use of the Joslin Vision Network versus conventional clinic-based ophthalmoscopy among the entire diabetic populations served by the Indian Health Service, the Department of Veterans Affairs, and the active duty Department of Defense. The economic perspective analyzed was that of each federal agency. Data sources for costs and outcomes included the published literature, epidemiologic data, administrative data, market prices, and expert opinion. Outcome measures included the number of true positive cases of proliferative diabetic retinopathy detected, the number of patients treated with panretinal laser photocoagulation, and the number of cases of severe vision loss averted. In the base-case analyses, the Joslin Vision Network was the dominant strategy in all but two of the nine modeled scenarios, meaning that it was both less costly and more effective. In the active duty Department of Defense population, the Joslin Vision Network would be more effective but cost an extra 1,618 dollars per additional patient treated with panretinal laser photo-coagulation and an additional 13,748 dollars per severe vision loss event averted. Based on our economic model, the Joslin Vision Network has the potential to be more effective than clinic-based ophthalmoscopy for detecting proliferative diabetic retinopathy and averting cases of severe vision loss, and may do so at lower cost.

Telehealth practice recommendations for diabetic retinopathy

Telehealth holds the promise of increased adherence to evidenced-based medicine and improved consistency of care. Goals for an ocular telehealth program include preserving vision, reducing vision loss, and providing better access to medicine. Establishing recommendations for an ocular telehealth program may improve clinical outcomes and promote informed and reasonable patient expectations. This document addresses current diabetic retinopathy telehealth clinical and administrative issues and provides recommendations for designing and implementing a diabetic retinopathy ocular telehealth care program. The recommendations also form the basis for evaluating diabetic retinopathy telehealth techniques and technologies. Recommendations in this document are based on careful reviews of current evidence, medical literature and clinical practice. They do not, however, replace sound medical judgment or traditional clinical decision-making. "Telehealth Practice Recommendations for Diabetic Retinopathy" will be annually reviewed and updated to reflect evolving technologies and clinical guidelines.

Perioperative management of type 1 diabetes mellitus

Clearly, perioperative management of diabetic patients requires thorough preoperative evaluation and planning whenever possible. A firm understanding of the pathophysiology of type 1 diabetes mellitus, the metabolic stress response, and the interactions between various forms of insulin and other variables such as supplemental nutrition and glucocorticoids can greatly assist in achieving a positive outcome. Consultation with an endocrinologist, internist, or other primary care provider comfortable with managing type 1 diabetes patients is strongly recommended to assist in the details of in-patient care and overseeing of proper ancillary support. It may also be helpful to allow the patient to function as an active decision-maker in the coordination of care, especially because a large percentage of type 1 diabetes patients (particularly those who are on insulin pumps) are well-educated about their disease process and their own physiologic idiosyncrasies. This knowledge can save valuable time and effort toward achieving the ultimate united goal of avoiding perioperative morbidity and mortality by maximizing glycemic control.

A model to determine workforce needs for endocrinologists in the United States until 2020

The objective of this study was to define the workforce needs for the specialty of Endocrinology, Diabetes, and Metabolism in the United States between 1999 and 2020. An interactive model of factors likely to influence the balance between the supply and demand of endocrinologists during the next 20 years was constructed. The model used data from a wide range of sources and was developed under the guidance of a panel of experts derived from sponsoring organizations of endocrinologists. We determined current and projected numbers and demographics of endocrinologists in the U.S. workforce and the anticipated balance between supply and demand from 1999 to 2020. There were 3,623 adult endocrinologists in the workforce in 1999, of which 2,389 (66%) were in office-based practice. Their median age was 49 years. Both total office visits and services performed by endocrinologists (particularly for diabetes) increased substantially during the 1990s. Waiting time for an initial appointment is presently longer for endocrinologists than for other physicians. Compared with a balanced, largely closed-staff health maintenance organization, the current national supply of endocrinologists is estimated to be 12% lower than demand. The number of endocrinologists entering the market has continuously fallen over the previous 5 years, from 200 in 1995 to 171 in 1999. Even if this downward trend were abruptly stopped, the model predicts that demand will exceed supply from now until 2020. While this gap narrows from 2000 to 2008 due to projected growth of managed care, it widens thereafter due to the aging of both the population and the endocrine workforce. Inclusion of other factors such as projected real income growth and increased prevalence of age-related endocrine disorders (e.g., diabetes and osteoporosis) further accentuates the deficit. If the number of endocrinologists entering the workforce remains at 1999 levels, demand will continue to exceed supply from now through 2020 for adult endocrinologists, and the gap will widen progressively from 2010 onward. The present analysis indicates that the number of endocrinologists entering the workforce will not be sufficient to meet future demand. These data suggest that steps should be taken to stop the ongoing decline in the number of endocrinologists in training and consideration should be given to actions designed to increase the number of endocrinologists in practice in the years ahead.

A model to determine workforce needs for endocrinologists in the United States until 2020

The objective of this study was to define the workforce needs for the specialty of endocrinology, diabetes, and metabolism in the United States between 1999 and 2020. An interactive model of factors likely to influence the balance between the supply and demand of endocrinologists during the next 20 yr was constructed. The model used data from a wide range of sources and was developed under the guidance of a panel of experts derived from sponsoring organizations of endocrinologists. We determined current and projected numbers and demographics of endocrinologists in the United States workforce and the anticipated balance between supply and demand from 1999 to 2020. There were 3,623 adult endocrinologists in the workforce in 1999, of which 2,389 (66%) were in office-based practice. Their median age was 49 yr. Both total office visits and services performed by endocrinologists (particularly for diabetes) increased substantially during the 1990s. Waiting time for an initial appointment is presently longer for endocrinologists than for other physicians. Compared with a balanced, largely closed-staff health maintenance organization, the current national supply of endocrinologists is estimated to be 12% lower than demand. The number of endocrinologists entering the market has continuously fallen over the previous 5 yr, from 200 in 1995 to 171 in 1999. Even if this downward trend were abruptly stopped, the model predicts that demand will exceed supply from now until 2020. Whereas this gap narrows from 2000 to 2008 due to projected growth of managed care, it widens thereafter due to the aging of both the population and the endocrine workforce. Inclusion of other factors such as projected real income growth and increased prevalence of age-related endocrine disorders (e.g. diabetes and osteoporosis) further accentuates the deficit. If the number of endocrinologists entering the workforce remains at 1999 levels, demand will continue to exceed supply from now through 2020 for adult endocrinologists, and the gap will widen progressively from 2010 onward. The present analysis indicates that the number of endocrinologists entering the workforce will not be sufficient to meet future demand. These data suggest that steps should be taken to stop the ongoing decline in the number of endocrinologists in training and consideration should be given to actions designed to increase the number of endocrinologists in practice in the years ahead.

A model to determine workforce needs for endocrinologists in the United States until 2020

The objective of this study was to define the workforce needs for the specialty of Endocrinology, Diabetes, and Metabolism in the United States between 1999 and 2020. An interactive model of factors likely to influence the balance between the supply and demand of endocrinologists during the next 20 years was constructed. The model used data from a wide range of sources and was developed under the guidance of a panel of experts derived from sponsoring organizations of endocrinologists. We determined current and projected numbers and demographics of endocrinologists in the U.S. workforce and the anticipated balance between supply and demand from 1999 to 2020. There were 3,623 adult endocrinologists in the workforce in 1999, of whom 2,389 (66%) were in office-based practice. Their median age was 49 years. Both total office visits and services performed by endocrinologists (particularly for diabetes) increased substantially during the 1990s. Waiting time for an initial appointment is presently longer for endocrinologists than for other physicians. Compared with a balanced, largely closed-staff health maintenance organization, the current national supply of endocrinologists is estimated to be 12% lower than demand. The number of endocrinologists entering the market has continuously fallen over the previous 5 years, from 200 in 1995 to 171 in 1999. Even if this downward trend were abruptly stopped, the model predicts that demand will exceed supply from now until 2020. While this gap narrows from 2000 to 2008 due to projected growth of managed care, it widens thereafter due to the aging of both the population and the endocrine workforce. Inclusion of other factors such as projected real income growth and increased prevalence of age-related endocrine disorders (e.g., diabetes and osteoporosis) further accentuates the deficit. If the number of endocrinologists entering the workforce remains at 1999 levels, demand will continue to exceed supply from now through 2020 for adult endocrinologists, and the gap will widen progressively from 2010 onward. The present analysis indicates that the number of endocrinologists entering the workforce will not be sufficient to meet future demand. These data suggest that steps should be taken to stop the ongoing decline in the number of endocrinologists in training and consideration should be given to actions designed to increase the number of endocrinologists in practice in the years ahead.

A wireless diabetes management and communication system

Current diabetes management requires the collection of a large volume of data by the patient for analysis by his or her provider. There are numerous practical and technical barriers to doing this effectively and efficiently. In addition, the calculation of the correct insulin dose is complex because it requires considering anticipated carbohydrate consumption and exercise in addition to the current blood glucose level. A Diabetes Management and Communication System (DMCS) has been developed using a Compaq iPAQ Pocket PC with a Sprint PCS wireless AirCard. This system circumvents the problem of multiple proprietary programs for each brand of meter and permits the accurate determination of the proper insulin dose. Privacy is maintained by using only the iPAQ serial number as the patient identifier with access to the website protected by unique patient and provider passwords. The iPAQ was programmed with formulas that included: insulin sensitivity factor, current glucose level, amount of carbohydrates, appropriate carbohydrate:insulin ratio for that meal, and duration/intensity of exercise. Once the information is entered, an insulin dose is calculated, although an alternative dose can be selected. The data are downloaded to http://www.HealthSentry.net, where they are displayed in both tabular and graphic form. The patient may view the glucose data in both tabular and graphic form on the iPAQ. Thus a DMCS has been developed to assist patients and providers in improving glycemic control. A proof-of-concept study is underway to determine the effectiveness of the DMCS in patients with Type 1 diabetes mellitus who are currently using insulin pumps.

Amenorrhea in Olympic marathon runners

Women who exercise heavily may develop secondary amenorrhea. Since the mechanism of so-called "runner's amenorrhea" has not been conclusively established, the authors examined the occurrence of amenorrhea in one of the most intensively exercising groups of female runners in the United States (average, 70 miles/week): those women participating in the marathon trials for the 1984 Olympics. Nineteen percent of these Olympic runners were amenorrheic. When compared with eumenorrheic marathon runners, these amenorrheic runners were significantly (P less than 0.05) younger (24.8 +/- 1.2 [standard error of the mean] versus 30.8 +/- 0.8 years), lighter (108.4 +/- 2.5 versus 114.6 +/- 1.7 lb), and leaner (11.2 +/- 0.5 versus 12.5 +/- 0.3% body fat). There were no differences between the two groups in weekly training mileage, proportion completing the marathon trial, finishing time, basal serum prolactin, or postmarathon serum prolactin. Although basal serum cortisol was slightly higher in the amenorrheic group (26.6 +/- 0.8 versus 22.3 +/- 0.7 micrograms/dl; P less than 0.05), postmarathon serum cortisol was similar in the two groups. This study supports the concept that training intensity above a certain threshold seems to have little effect on the development of runner's amenorrhea, and vigorously training national caliber marathon runners have a lower incidence of amenorrhea than previously predicted.

Exaggerated gonadotropin response to luteinizing hormone-releasing hormone in amenorrheic runners

Most studies of exercise-induced amenorrhea have compared amenorrheic athletes (usually runners) with sedentary control subjects. Such comparisons will identify hormonal changes that develop as a result of exercise training but cannot determine which of these changes play a role in causing amenorrhea. To obviate this problem, we assessed reproductive hormone status in a group of five amenorrheic runners and compared them to a group of six eumenorrheic runners matched for body fatness, training intensity, and exercise performance. Compared to the eumenorrheic runners, the amenorrheic runners had lower serum estradiol concentrations, similar basal serum luteinizing hormone and follicle-stimulating hormone concentrations, and exaggerated responses of serum gonadotropins after administration of luteinizing hormone-releasing hormone (100 micrograms intravenous bolus). Serum prolactin levels, both basally and after thyrotropin-releasing hormone administration (500 micrograms intravenous bolus) or treadmill exercise, was similar in the two groups, as were serum thyroid function tests (including thyrotropin response to thyrotropin-releasing hormone). Changes in serum cortisol levels after short-term treadmill exercise were similar in both groups, and serum testosterone levels increased after exercise only in the eumenorrheic group. In neither group did such exercise change serum luteinizing hormone, follicle-stimulating hormone, or thyrotropin levels. We concluded that exercise-induced amenorrhea is not solely related to the development of increased prolactin output after exercise training. The exaggerated gonadotropin response to luteinizing hormone-releasing hormone seen in amenorrheic runners in comparison with matched eumenorrheic runners is consistent with a hypothalamic etiology for the menstrual dysfunction, analogous to that previously described in "stress-induced" or "psychogenic" amenorrhea.

Nutritional survey of highly trained women runners

Mean daily intakes from 3-day dietary records for calories, energy-providing nutrients, and selected minerals were calculated for 51 highly trained women runners. Selected blood constituents relating to mineral status were also measured. Intakes of calcium, magnesium, iron, and copper were above the amounts recommended by the National Research Council whereas zinc intake was below the recommended dietary allowances (RDA). Caloric intakes, although above the RDA for sedentary women, appeared low for women running 10 miles/day. Concentrations of serum ferritin and plasma zinc were indicative of marginal iron and zinc status in many of the women. Whether the nutrient content of the diets consumed by these women is adequate relative to energy output or whether training lowers nutrient requirements by enhancing metabolic efficiency will require further investigation.

Nutritional intakes and status of highly trained amenorrheic and eumenorrheic women runners

This study was conducted to determine whether nutritional status contributes to the amenorrhea associated with long distance running. Dietary intakes and biochemical measures of nutritional status were compared in highly trained amenorrheic (AM) and eumenorrheic (EU) women runners matched for height, weight, percent fat (11% to 12%) and training distance (113 km/week). Serum estradiol (E2) (EU, 104.7 pg/ml, versus AM, 22.5 pg/ml) and cortisol (EU, 22.4 micrograms/dl, versus AM, 26.6 micrograms/dl) concentrations differed between the two groups. Three-day dietary records revealed that fat intake by AM runners was significantly lower than by EU runners (EU, 97 gm/day, versus AM, 66 gm/day). AM runners consumed large amounts of vitamin A activity, probably in the form of B-carotene, and fairly high quantities of crude fiber. Zinc intake by AM runners was well below the recommended dietary allowances (RDA), compared with EU runners (EU, 15.4 mg, versus AM, 10.9 mg). Further, plasma zinc tended to be lower for the AM runners (EU, 85.7 micrograms/dl, versus AM, 81.2 micrograms/dl). It was concluded that the potential contributions of dietary fat, B-carotene, and zinc to inducing changes in menstrual function and the metabolism of certain hormones should be investigated.

Comparative antiandrogenic potency of spironolactone and cimetidine: assessment by the chicken cockscomb topical bioassay

Spironolactone and cimetidine are effective antiandrogens in vivo, although they differ by five orders of magnitude in affinity for androgen receptors in vitro. To explore this discrepancy, we directly compared the antiandrogenic potency of these two compounds in vivo using the chicken cockscomb topical bioassay. In this assay, the growth of the androgen sensitive cockscomb of immature chicks after stimulation by various doses of androgen (dihydrotestosterone 5, 20, or 100 micrograms/day sc) is inhibited by antiandrogens in cream vehicle applied topically to the cockscomb itself. At low levels of androgen stimulation (5 micrograms/day), 0.5% topical cimetidine produced maximal suppression of cockscomb growth, while at high levels of androgen stimulation 100 micrograms/day), topical cimetidine in concentrations as high as 4% did not suppress cockscomb growth. In contrast, topical spironolactone in concentrations as low as 0.06% produced maximal inhibition of cockscomb growth at all androgen doses. Using an intermediate androgen dose (20 micrograms/day), the minimally effective antiandrogenic concentration of topical cimetidine was between 0.5 and 1.0%, while that for topical spironolactone was less than 0.001%. We conclude that the chicken cockscomb topical bioassay is a useful method for assessing relative potency of antiandrogens. With this method, spironolactone appears to be at least 500 times as strong an antiandrogen in vivo as cimetidine.

Hypogonadotropic hypogonadism in nephrotic rats: increased sensitivity to negative feedback effects of testosterone

Pituitary-testicular function was examined in adult male rats with aminonucleoside-induced nephrotic syndrome as a model for similar disease in humans. Nephrotic rats developed androgen deficiency, as manifested by decreased prostate and seminal vesicle weights, lower serum total and free testosterone levels, and reduced testosterone release from testes incubated in vitro. Despite hypoandrogenism, the weight and histologic appearance of the testes (light microscopy) were not affected in nephrotic rats. This androgen deficiency seemed to be a consequence of decreased gonadotropin output rather than primary testicular failure, since both pituitary gonadotropin content and serum gonadotropin levels (basally and after luteinizing hormone releasing factor; LHRH) were reduced in nephrotic rats. In addition, the percentage increase in testosterone release by testes incubated in vitro after addition of exogenous gonadotropin was similar in nephrotic and control groups. However, gonadotropin output in nephrotic rats was not impaired in the absence of testis, since no reduction was seen in either post-castration serum gonadotropin levels in vivo or gonadotropin release from pituitaries incubated in vitro. This presumed inhibitory effect of the testis on gonadotropin output in nephrotic rats was confirmed directly by demonstrating an increased sensitivity to testosterone-mediated suppression of gonadotropins in castrate animals in vivo. The presence or absence of albumin also seemed to modulate the suppressive effect of testosterone on gonadotropin output from normal pituitaries incubated in vitro. We conclude that nephrotic male rats develop hypogonadotropic hypogonadism secondary to an increase in sensitivity of the pituitary to the negative feedback effects of testosterone.