Expression of the insulin-like growth factor (IGF)-I and -II and the IGF-I and -II receptor genes during postnatal development of the rat ovary.

Solution hybridization/RNase protection assays were used to study the developmental expression of the insulin-like growth factor-I (IGF-I), IGF-II, IGF-I receptor, and IGF-II/mannose-6-phosphate receptor genes in the rat ovary between postnatal days 1-80. Maximal IGF-I mRNA levels occurred during the 15- to 25-day postnatal period, and the level on day 20 represented a 9-fold increase over the baseline at earlier and later stages. IGF-II mRNA levels were maximal during the 1- to 5-day postnatal period and subsequently declined to undetectable levels after day 10. IGF-I receptor mRNA levels increased 10-fold to a maximum in the 20- to 25-day postnatal period. This pattern was similar to the developmental pattern of [125I]IGF-I binding in the ovary. Two apparent peaks of IGF-II/mannose-6-phosphate receptor mRNA levels were seen, on day 20 and between days 50-80. These specific and significant changes in the expression of the genes encoding the IGFs and their receptors suggest a role for the IGF system in postnatal ovarian development.

Soy protein and isoflavones: their effects on blood lipids and bone density in postmenopausal women.

The effects of soy protein (40 g/d) containing moderate and higher concentrations of isoflavones on blood lipid profiles, mononuclear cell LDL receptor messenger RNA, and bone mineral density and content were investigated in 66 free-living, hypercholesterolemic, postmenopausal women during a 6-mo, parallel-group, double-blind trial with 3 interventions. After a control period of 14 d, during which subjects followed a National Cholesterol Education Program Step I low-fat, low-cholesterol diet, all subjects were randomly assigned to 1 of 3 dietary groups: Step I diet with 40 g protein/d obtained from casein and nonfat dry milk (CNFDM), Step I diet with 40 g protein/d from isolated soy protein containing 1.39 mg isoflavones/g protein (ISP56), or Step I diet with 40 g protein/d from isolated soy protein containing 2.25 mg isoflavones/g protein (ISP90). Total and regional bone mineral content and density were assessed. Non-HDL cholesterol for both ISP56 and ISP90 groups was reduced compared with the CNFDM group (P < 0.05). HDL cholesterol increased in both ISP56 and ISP90 groups (P < 0.05). Mononuclear cell LDL receptor mRNA was increased in subjects consuming ISP56 or ISP90 compared with those consuming CNFDM (P < 0.05). Significant increases occurred in both bone mineral content and density in the lumbar spine but not elsewhere for the ISP90 group compared with the control group (P < 0.05). Intake of soy protein at both isoflavone concentrations for 6 mo may decrease the risk factors associated with cardiovascular disease in postmenopausal women. However, only the higher isoflavone-containing product protected against spinal bone loss.

A comparison of bone mineral densities among female athletes in impact loading and active loading sports.

The purpose of this study was to compare bone mineral densities (BMD) of collegiate female athletes who compete in impact loading sports; volleyball players (N = 8) and gymnasts (N = 13), to a group of athletes who participate in an active loading sport; swimmers (N = 7), and a group of controls (N = 17). All of the volleyball, swimming, and control subjects were eumenorrheic (10-12 cycles/year), whereas two of the gymnasts were amenorrheic (0-3 cycles/year), eight were oligomenorrheic (4-8 cycles/year), and three were eumenorrheic (10-12 cycles/year). Lumbar spine, proximal femur, and total body BMD were measured with dual-energy X-ray absorptiometry. The groups were compared with respect to the following regions: lumbar spine (L1-4); femoral neck; Ward's triangle; right and left arms; right and left legs; pelvis; and torso. When controlling for differences in height and weight the impact loading group (volleyball and gymnastic) had significantly greater BMD at the lumbar spine, femoral neck, Ward's Triangle, and total body when compared to the active loading (swimming) and control groups. The regional analysis from the total body scan revealed that the gymnasts had significantly (p < 0.05) greater BMD than all other groups at the right and left arm sites. The impact loading groups (gymnastic and volleyball) had a greater BMD in the legs and pelvis than the active loading (swimming) and control groups. Furthermore, the impact loading group had a greater torso BMD than the control group. There were no differences at any site between the active loading group (swimming) and control groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Association between mullerian duct malformations and Asherman syndrome in infertile women.

Mullerian duct malformations were found in 8% and Asherman syndrome in 4.8% of 537 infertile women undergoing hysterosalpingogram and/or hysteroscopy among 840 consecutive infertile couples evaluated. Among the 43 patients with mullerian duct malformations and the 26 with Asherman syndrome, seven had both mullerian duct malformations and Asherman syndrome (16 and 29%, respectively). This association was highly significant (P less than .005), especially for those patients with a septate uterus (P less than .001). Secondary infertility was present in 44% of the 840 infertile couples; 41% of the 537 women undergoing hysterosalpingogram and/or hysteroscopy and 44% of the patients with mullerian duct malformations versus 81% of those with Asherman syndrome (P less than .001). Prior reproductive performance was dismal for the patients with Asherman syndrome and/or mullerian duct malformations, and among all classes of mullerian duct malformations, and among all classes of mullerian duct malformations. The predisposing and causative factors leading to Asherman syndrome can be observed with mullerian duct malformations and a strong association in this population of infertile couples is reported for the first time.

Efficacy of assisted reproductive technology during diagnostic and operative infertility laparoscopy.

Women being evaluated for infertility were offered assisted reproductive technology at the time of diagnostic laparoscopy. Oocyte retrieval was performed after ovulation induction in 33 women, of whom 19 had concurrent operative laparoscopy. Gamete intrafallopian transfer (GIFT) or in vitro fertilization (IVF) and embryo transfer were performed subsequently depending on laparoscopic assessment of pelvic architecture, oocyte maturity, and semen parameters. The clinical pregnancy rate was 24% per cycle and 28% per gamete or embryo transfer (four pregnancies after GIFT and four after IVF/embryo transfer). The clinical pregnancy rate per transfer did not differ significantly between the 19 women who had therapeutic operations in conjunction with laparoscopy (lysis of adhesions and/or fulguration of endometriosis) and the 13 who did not (25 versus 30%; P greater than .05). Assisted reproductive technology can be performed successfully during diagnostic infertility laparoscopy. Operative endoscopic manipulation did not adversely influence pregnancy outcome.

Effects of conjugated equine estrogen with and without three different progestogens on lipoproteins, high-density lipoprotein subfractions, and apolipoprotein A-I.

The effects of conjugated equine estrogen and subsequent cyclical progestogen supplementation on lipoprotein and apolipoprotein A-I levels were investigated in three groups of postmenopausal women. Unopposed conjugated equine estrogen (0.625 mg) lowered total cholesterol 4-8% and low-density lipoprotein (LDL) cholesterol 12-19% below pre-treatment levels in all three groups. Levels of high-density lipoprotein (HDL) cholesterol and apolipoprotein A-I were increased 9-13 and 9-18%, respectively, with unopposed estrogen. The increase in HDL cholesterol was mainly due to increases in the high-density lipoprotein2 (HDL2) subfraction. Addition of medroxyprogesterone acetate, norethindrone acetate, or d,l-norgestrel at doses shown previously to provide protection against endometrial hyperplasia reversed some of the beneficial estrogen effects, reducing levels of HDL cholesterol 14-17%, HDL2 cholesterol 22-37%, and apolipoprotein A-I 11-15% from those obtained with unopposed estrogen. The LDL cholesterol levels fell 12-19% with unopposed estrogen but remained 7-12% below baseline when progestogens were added. These observations demonstrate that after 3 months of treatment, all three progestogens reversed some of the favorable effects of unopposed estrogen on lipoproteins but permitted a continued modest reduction in LDL cholesterol.

Quantitative and qualitative changes in lipids, lipoproteins, apolipoprotein A-I, and sex hormone-binding globulin due to two doses of conjugated equine estrogen with and without a progestin.

OBJECTIVE: To determine whether the quantitative and qualitative effects on lipoproteins differ between two doses of conjugated equine estrogen before and after progestin administration. METHODS: We randomized 103 postmenopausal women into a control group and into two groups receiving either 0.625 mg or 1.25 mg of conjugated equine estrogen for 4 months and then the same estrogen dose plus cyclic medroxyprogesterone acetate for 8 months. RESULTS: Both estrogen doses similarly lowered (P < .01) low-density lipoprotein (LDL) cholesterol and raised (P < .01) high-density lipoprotein (HDL) cholesterol, apolipoprotein A-I, triglyceride levels of all lipoproteins, and sex hormone-binding globulin capacity. Cyclic addition of the progestin reduced HDL cholesterol (P < .01) and apolipoprotein A-I (P < .05), but not LDL cholesterol in either estrogen group. A greater lowering of HDL cholesterol (P < .05) in response to the progestin was seen with the 0.625-mg dose of estrogen. Estrogen-induced triglyceride enrichment of HDL and LDL was not reversed by the progestin. CONCLUSION: The only significant quantitative difference in lipoprotein levels between the doses of conjugated equine estrogen before or after administration of medroxyprogesterone acetate was a greater decline in HDL cholesterol levels with the lower dose after 4 months of the progestin. This difference was not sustained over time. There were no differences between doses in the estrogen-induced triglyceride enrichment of lipoproteins, and these qualitative changes were not affected by the progestin.

Diethylstilbestrol exposure in utero and endometriosis in infertile females.

Endometriosis was found in 39% and in utero diethylstilbestrol (DES) exposure in 5% of 397 infertile women who had undergone laparoscopy and/or laparotomy among 750 consecutively evaluated infertile couples. Fifty percent of the DES-exposed infertile women also had endometriosis, similar to the 39% with endometriosis among non-DES-exposed women. Cervical stenosis was found in 25% of all DES-exposed patients and in 83% of those who had undergone cryocautery or conization. However, 40% did not have endometriosis. Thus, while the frequency of endometriosis and cervical stenosis is extremely high in infertile women exposed in utero to DES, a significant association beyond that found in non-DES-exposed patients could not be established. Some of the infertility may be associated with cervical stenosis alone.

PIP: Endometriosis was found in 39% and in utero diethylstilbestrol (DES) exposure in 5% of 397 infertile women who had undergone laparoscopy and/or laparotomy among 750 consecutively evaluated infertile couples. 50% of the DES exposed infertile women also had endometriosis, similar to the 39% with endometriosis among non-DES exposed women. Cervical stenosis was found in 25% of all DES-exposed patients and in 83% of those who had undergone cryocautery or conization. However, 40% did not have endometriosis. Thus, while the frequency of endometriosis and cervical stenosis is extremely high in infertile women exposed to DES in utero, a significant association beyond that found in non-DES exposed women could not be established. Some infertility may be associated with cervical stenosis alone.

Utility of in vitro fertilization at diagnostic laparoscopy.

OBJECTIVE: To compare stimulation and outcome variables for IVF in stimulated cycles when ova are retrieved during diagnostic infertility laparoscopy versus transvaginal ultrasound (US) directed retrieval and to investigate the presence of unexpected failed fertilization in the diagnostic laparoscopy group, which allows an opportunity to diagnosis an etiology of infertility based on gamete interaction. DESIGN: Consecutive patients who needed infertility diagnostic laparoscopy and agreed to combination with IVF were compared with concurrent patients undergoing transvaginal US IVF. Male factor screening parameters (semen analysis, sperm penetrating assay) and resultant fertilization were analyzed for these patients. SETTING: The George Washington University Hospital, a tertiary referral center offering assisted reproductive technologies. Patients for diagnostic laparoscopy combined with IVF were enrolled in the Program of Oocyte Retrieval at Diagnostic Laparoscopy (PORDL). PARTICIPANTS: One hundred twenty-four women enrolled for diagnostic laparoscopy combined with IVF; 237 women were concurrently enrolled for transvaginal US IVF. RESULTS: Response variables (number of follicles, days of monitoring, ampules of hMG, maximum E2) between the two groups were similar. Outcome variables (ova retrieved, ova fertilized, ova cleaved, clinical pregnancy rate per embryo transferred) were similar despite a significantly higher number of embryos transferred for the transvaginal US group. The clinical pregnancy rate per cycle was similar, 26% versus 28% for the women in the transvaginal US versus those women in the PORDL group, as was the clinical pregnancy rate per ET, 31% versus 34%, respectively. The number of fertilized ova for each group was not significantly different: 5.5 +/- 0.3 for the transvaginal group versus 4.8 +/- 0.4 for the PORDL group. Patients in the PORDL group with a known male factor (group B) had a lower fertilization rate than those with no male factor (group A). Within the group A with no detectable male factor prospectively, 17.2% had unexpectedly poor fertilization (group A1), whereas the rest of the group A patients had higher fertilization rates as was expected (group A2). The clinical pregnancy rate per ET for group A1 was 0% compared with 43.4% for the group A2 patients. CONCLUSIONS: In vitro fertilization can be successfully performed during diagnostic laparoscopy yielding comparable results to transvaginal ultrasound IVF while gaining diagnostic information concerning sperm-ova interaction (i.e., fertilization).

Smoking and reproduction.

PIP: This article reviews currently available epidemiologic and experimental data on the effects of cigarette smoking on reproductive health. Specifically addressed are the evidence for and possible physiologic causes of disturbance in 3 areas: female fertility, male fertility, and the effect of smoking on reproduction and pregnancy. Approximately 30% of women and 36% of men of reproductive age in the US are smokers. The literature offers clear support for an association between smoking and decreased female fecundity and fertility, especially with a relationship to primary tubal infertility. Cigarette smoke appears to have adverse effects along a continuum of preimplantation and implantation reproductive processes, including gamete production and function, ovulation and cyclicity, fertilization, early embryonic cleavage, embryo transport, and implantation. In men, there is clear evidence that smoking results in fewer and less motile sperm as well as a lower proportion of normally shaped sperm; however, it remains unclear whether this impairment in spermatogenesis results in clinical impairment of fertility. Studies have demonstrated a significant increase among smoker both in the risk of spontaneously aborting a chromosomally normal fetus and in the risk of spontaneously aborting a chromosomally normal fetus and in the risk of prematurity. Moreover, smoling has been shown to cause a 150-300 gram decrease interm infant birthweight. Al these risks to fecundity and pregnancy outcome are minimized or absent in former smokers. It is stressed that efforts to persuade women to stop smoking have been inadequate. It is particularly imperative for women who have had divviculties conceving or have had a history of miscarraiges to give up cigarette smoking.^ieng

Factors influencing murine embryo bioassay: effects of proteins, aging of medium, and surgical glove coatings.

The 2-cell murine embryo bioassay as quality control for human in vitro fertilization (IVF) was used to evaluate the effects of protein supplements, medium aging, and surgical glove coatings. Ham's F-10 medium (GIBCO, Grand Island, NY) without protein supplementation supported growth of the 2-cell embryos to blastocysts. Addition of bovine serum albumin (BSA), fetal cord serum (FCS), or maternal serum (MS) did not enhance or reduce the blastulation rates (medium alone, 89.4%; BSA, 86.4%; FCS, 90%; MS, 74.7%). Unsupplemented Ham's F-10 medium was found to contain three major peaks of approximately 50,000 daltons and several minor peaks, analyzed on high-performance liquid chromatography (HPLC) and sodium sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), suggesting the presence of protein(s) in the medium itself. The storing of medium up to 425 days at 4 degrees C affected neither the HPLC profile nor its ability to support embryo growth (blastulation rates: fresh, 84%; stored 150 to 425 days, 77.7%). The coating of surgical gloves affected embryo growth. Both talc-coated (TC) and "talc-free," starch-coated (SC) surgical gloves were found to be progressively embryotoxic when they touched the medium for increasing lengths of time, compared with uncoated latex (UL) gloves and untouched control medium. Quality control of medium preparation and handling in murine embryo bioassay is reemphasized, with requirements for protein supplementation, use of fresh medium, and possible contamination with even talc-free, SC surgical gloves reevaluated.

Selective inhibition of follicle-stimulating hormone by porcine follicular fluid extracts in the monkey: effects on midcycle surges and pulsatile secretion.

Nonsteroidal factor(s) in porcine follicular fluid (pFF) can selectively suppress tonic follicle-stimulating hormone (FSH) concentrations when administered in the follicular phase to monkeys. Here it is demonstrated that when administered in either the early follicular phase or in the midst of the spontaneous preovulatory estradiol (E2) surge (E2 greater than or equal to 200 pg/ml), pFF preferentially inhibits FSH or blocks the FSH surge, respectively, whereas immunoassayable and bioassayable luteinizing hormone (LH) surges persist. Delay in the timing of ovulation uniformly follows follicular phase pFF administration, and corpus luteal insufficiency is often seen. The inhibitions of FSH in circulation were achieved by a decrease in amplitude and frequency of FSH pulses. No discernible effect on LH pulsatility was observed.

Achieving multiple-order embryo transfer identifies women over 40 years of age with improved in vitro fertilization outcome.

OBJECTIVE: To define factors in patients > or = 40 years that may improve outcome and provide prognosis for success in IVF-ET. DESIGN: Retrospective. SETTING: University infertility center. PATIENTS: Patients (n = 501) undergoing IVF-ET from 1987 to 1994. INTERVENTIONS: IVF-ET (n = 713 cycles) with GnRH-analogue suppression and hMG stimulation. MAIN OUTCOME MEASURES: We evaluated data including age, diagnosis, prestimulation (day 3) FSH and E2, hMG ampules used, days of monitoring, follicle number and size, maximum E2, ova retrieved, cancellation rate, clinical pregnancy, nidation, and miscarriage rates. RESULTS: Overall, patients > or = 40 years had significantly decreased pregnancy rates (PRs), response to stimulation, and increased miscarriage rates. However, if these patients had four or more embryos transferred, their response and PRs (34.4% per ET) were not significantly different from younger women (47.7% per ET). The majority (77.8%) of pregnancies in women > or = 40 years occurred when four or more embryos were transferred. CONCLUSION: A subset (49%) of women > or = 40 years undergoing IVF-ET will respond to ovarian stimulation well enough to result in four or more embryos available for transfer with a resultant PR similar to that observed in younger patients. We recommend consideration of an attempt at IVF-ET before recommending oocyte donation.

Photodynamic therapy of rabbit endometrial transplants: a model for treatment of endometriosis.

The potential of photodynamic therapy for endometriosis was evaluated by autotransplantation of endometrial tissue in 15 female virgin New Zealand white rabbits. After maturation, 14 animals were injected intravenously with 10 mg/kg of dihematoporphyrin ether (DHE) and, 24 hours later, transplants were exposed to 630 nm light at 100 to 210 mW/cm2. Sixteen transplants received 100 J/cm2, 10 transplants received 50 J/cm2; 13 untreated transplants served as controls. In the remaining animal that did not receive DHE, 3 transplants were irradiated with 100 J/cm2. Six days after treatment, transplants were harvested with the underlying musculature, and multiple sections were examined histopathologically. Complete endometrial epithelial destruction was seen in 13 of 16 transplants (81%) in the 100 J/cm2 group and in 6 of 10 transplants (60%) in the 50-J/cm2 group. Nearly complete endometrial epithelial destruction was seen in 2 other transplants in each group. No damage occurred in either the 3 transplants that received 100 J/cm2 without prior DHE or in the 13 transplants with DHE and no irradiation. The sensitivity of ectopic rabbit endometrial tissue encourages further evaluation of photodynamic therapy for the treatment of human endometrial disorders.

Clomiphene citrate directly impairs endometrial receptivity in the mouse.

Clomiphene citrate (CC) has known antifecundity effects in animal models. To help define the site of action of this effect, we studied the direct effect of CC on endometrial receptivity by transferring embryos to hormonally prepared prepubertal mice. Prepubertal mice were begun on one of four blinded hormonal preparations consisting of two consecutive 3-day periods of daily injections: oil vehicle, oil-progesterone (P), estradiol (E2)-P, or CC-P. Blastocysts, which had not been exposed to CC, were then surgically transferred to these prepubertal recipients. Fourteen days after embryo transfer, implantations and term pregnancies were counted at necropsy. In this model, CC demonstrated no estrogen agonist effect, and had a significant adverse effect on endometrial receptivity. CC appeared to lower fecundity by a direct endometrial effect.

Fluorescent detection of rabbit endometrial implants resulting from monodispersed viable cell suspensions.

A model for early stage endometriosis was prepared in rabbits by intraperitoneal injection of monodispersed viable endometrial cells. With this model, we have found that DHE fluorescence increases the sensitivity of detection of endometrial tissue. The potential experimental and clinical significance of ectopic endometrial detection by porphyrin fluorescence is enhanced by the recent report of endometrial transplant destruction by PDT. Although caution must be exercised for extrapolation from animal experiments to human conditions, these results encourage further evaluation of photosensitization for the study and potential treatment of disorders involving endometrial tissue.

Prognostic value of day 3 estradiol on in vitro fertilization outcome.

OBJECTIVE: To evaluate the prognostic value of day 3 E2 levels, independent of day 3 FSH levels, on responses to ovulation induction and subsequent pregnancy rates (PRs) in IVF-ET patients. DESIGN: Prospective, observational. SETTING: University-based tertiary care and private reproductive endocrine-infertility units. PATIENTS AND INTERVENTIONS: A total of 225 patients underwent 292 IVF cycles with luteal phase GnRH agonist suppression and hMG stimulation. MAIN OUTCOME MEASURES: We evaluated response and outcome data including age, day 3 FSH and E2 levels from a menstrual cycle before IVF, ampules of hMG used, maximum E2 level, cancellation rates, and clinical PR. RESULTS: Despite similar age, number of ampules of hMG, and peak E2 levels, patients with an elevated E2 level (E2 > or = 80 pg/mL) (conversion factor to SI unit, 3.671) on day 3 of a cycle before IVF-ET achieved a lower PR per initiated cycle (14.8% versus 37.0%) and had a higher cancellation rate (18.5% versus 0.4%) compared with those with E2 levels < 80 pg/mL. Even when patients with elevated FSH levels (FSH > or = 15 mIU/mL) (conversion factor to SI unit, 1.00) were excluded (leaving 279 cycles), those with an elevated day 3 E2 still had a lower PR per initiated cycle (14.8% versus 38.9%) and maintained a higher cancellation rate (18.5% versus 0.4%). When the day 3 E2 was > or = 100 pg/mL there was a 33.3% cancellation rate and no pregnancies were achieved. CONCLUSION: Patients who presented with an elevated day 3 E2 (> or = 80 pg/mL) in a cycle before IVF-ET had a higher cancellation rate and achieved a lower PR independent of FSH level. A day 3 E2 level, in addition to a day 3 FSH level, appears very helpful in prospectively counseling patients regarding cancellation risk and ultimate IVF-ET success.

Danazol inhibits human adrenal 21-and 11 beta-hydroxylation in vitro.

The effects of danazol on steroidogenesis in vitro in the 16-20 week old human fetal adrenal were examined by studying: 1) danazol binding to adrenal microsomal and mitochondrial cytochrome P-450, and 2) enzyme kinetics of danazol inhibition of the adrenal microsomal 21-hydroxylase and the mitochondrial 11 beta-hydroxylase. The addition of danazol to preparations of adrenal microsomes or mitochondria elicited a type I cytochrome P-450 binding spectrum. Danazol bound to microsomal cytochrome P-450 binding spectrum. Danazol bound to microsomal cytochrome P-450 with a high affinity apparent spectral dissociation constant (KS) of 1 microM and with a lower affinity K's of 10 microM. Danazol bound to mitochondrial cytochrome P-450 with a KS of 5 microM. In addition, danazol competitively inhibited the microsomal 21-hydroxylase (apparent enzymatic inhibition constant KI = 0.8 microM) and the mitochondrial 11 beta-hydroxylase (KI = 3 microM). These findings demonstrate that low concentrations of danazol directly inhibit steroidogenesis in the human fetal adrenal in vitro.

Physical activity and bone mineral content in women aged 30 to 85 years.

The relationship of bone mineral content and level of physical activity was investigated in 83 Caucasian females, aged 30 to 85 yr. Bone mineral content was measured by photon absorptiometry at a site one-third the distance from the distal radius to the olecranon process. Anthropometric measurements were taken and percent fat estimated. Physical activity questionnaires were independently evaluated by five physical education professionals, and subjects were assigned to low (N = 19), moderate (N = 36), or high (N = 28) activity groups. A significant difference (P less than 0.05) was seen in bone mineral content and in bone mineral content divided by bone width between the most active group of women and the two less active groups, even with age and menstrual status as co-variates. Mean values for bone mineral content divided by bone width, when adjusted for age and menstrual status, were 0.622, 0.651, and 0.679 g . cm-2 for the low, moderate, and high activity groups, respectively. No difference was found between the moderate and low activity groups. Percent fat estimates and skinfold thicknesses showed that women in the high activity category were significantly leaner (P less than 0.05), although height, weight, and skeletal widths for the groups were equivalent. The data indicate that a high level of physical activity could be a factor in reducing age-related bone loss and in preserving lean body mass in women.

Differences in the subcomponents of fat-free body in relation to height between black and white children.

The individual subcomponents of fat-free body (FFB) in relation to height were investigated in 131 white (N = 85) and black (N = 46) males (MW, MB) and 108 white (N = 63) and black (N = 45) females (FW, FB), aged 8 to 18 years. Bone mineral content (BM), bone width (BW), and bone mineral index (BMI) were measured using photon absorptiometry; total body water (TBW) was measured by deuterium dilution; body density was measured by hydrostatic weighing, correcting for residual lung volume; and estimates of lean body mass (LBM) were made from total body potassium (40 K spectroscopy). The subcomponents of the FFB-BM, BW, BMI, TBW, and K-were regressed on the log of height to determine the exponent of the independent variable (Ht) that would most accurately predict the dependent variables (BM, BW, BMI, TBW, K) within gender and race. Regression equations were derived for each of the variables used to represent a subcomponent of the FFB on Ht. Significant (P < .05) racial differences were found in BW, with the MB having wider bones than the MW. Significant racial differences were observed in BMI with FB demonstrating a greater difference across height than FW. Racial differences in BM and TBW approached significance within the female sample. At heights greater than the mean of a typical pubescent child, the males had higher values for each of the variables, except for BMI, than did the females. The lower BMI values observed in males indicated that the rate at which male bones grow in width was greater than their rate of mineralization. Within the male sample, blacks had higher bone mineral than whites with the magnitude of these differences dependent on the variable under consideration. Within the female sample the blacks had greater amounts of BM and BMI in relation to height, while the whites had a greater amount of K. Therefore, the magnitude of the differences between blacks and whites in the subcomponents of the FFB are dependent on gender, stature, and the particular subcomponent of the FFB under consideration.