Characterizing the influence of vitamin D levels on IVF outcomes

BACKGROUND

Vitamin D plays a role in reproductive capacity. Recently, several investigators have demonstrated higher IVF pregnancy rates in vitamin D replete women. The objective of this study was to validate these findings and to further elucidate the role of vitamin D in reproduction among a diverse group of women.

METHODS

This was a retrospective cohort study in an academic tertiary care center of 188 infertile women undergoing IVF. Serum levels of vitamin D (25OH-D) were measured in previously frozen serum samples. The main outcome measure was clinical pregnancy, defined as sonographic presence of a heartbeat following IVF.

RESULTS

The relationship between vitamin D status and pregnancy rates differed by race (P < 0.01). Among non-Hispanic whites, pregnancy rates declined with progressively lower levels of vitamin D, while in Asians, the reverse was true. Adjusting for age and number and quality of embryos transferred among non-Hispanic whites, the odds of pregnancy were four times higher in vitamin D replete versus deficient patients. Live birth rates mirrored pregnancy rates. Vitamin D status was not associated with ovarian stimulation parameters or with markers of embryo quality.

CONCLUSIONS

Vitamin D deficiency is associated with lower pregnancy rates in non-Hispanic whites, but not in Asians, possibly due to their lower IVF success rates. Vitamin D deficiency was not correlated with ovarian stimulation parameters or with markers of embryo quality, suggesting its effect may be mediated through the endometrium.

IGF1 genotype, mean plasma level and breast cancer risk in the Hawaii/Los Angeles multiethnic cohort

The insulin-like growth factor 1 gene (IGF1) is a strong candidate gene for a breast cancer susceptibility model. We investigated a dinucleotide repeat 969 bp upstream from the transcription start site of the IGF1 gene for possible associations with plasma IGF1 levels and breast cancer risk in a multiethnic group of postmenopausal women. Furthermore, we investigated the relation between race/ethnicity, mean plasma IGF1 levels and breast cancer rates in the Hawaii/Los Angeles Multiethnic Cohort. The mean age-adjusted IGF1 level among Latino-American women, 116 ng ml(-1), was statistically significantly lower than the mean age-adjusted IGF1 levels for each of the three other racial/ethnic groups, African-American, Japanese-American and Non-Latino White women (146, 144 and 145 ng ml(-1), respectively) (P<0.0001). Latino-American women have the lowest breast cancer rates of any racial/ethnic group in the cohort. These results support the investigation of an expansion of the hypothesis for an important role of IGF1 in breast cancer tumorigenesis to different racial/ethnic groups and to postmenopausal women. It is unlikely that any involvement of IGF1 in breast cancer aetiology is mediated by the IGF1 dinucleotide repeat polymorphism, which was not significantly associated with circulating IGF1 levels nor breast cancer risk in this study. Research into relevant determinants of IGF1 levels in the blood must continue.

Clinical detection of sarcopenic obesity by bioelectrical impedance analysis

To assess whether bioelectrical impedance analysis (BIA) provides clinically useful information on body composition beyond that obtained from measuring height and weight, we clinically classified 306 obese patients (233 females and 73 males) into tertiles of increasing fat-free mass estimated by BIA. Because fat-free mass by BIA is an estimate of lean body mass, the lowest tertile was clinically defined as sarcopenic obesity (reduced lean body mass), as contrasted with proportionate or muscular obesity in the next two tertiles. Fat mass in patients in each of the above tertiles based on BIA was then compared with fat mass estimated by using the equations of Garrow and Webster with body mass index (weight/height2). BIA-estimated fat mass was 4.3 kg greater in the sarcopenic group (n = 102) than predicted from body mass index. Fat mass predicted by BIA in the proportionate (n = 102) and muscular (n = 102) groups differed by less than the SEE of fat mass predicted by BMI. In premenopausal women at increased risk of breast cancer BIA showed a high prevalence of sarcopenic obesity (28/30) in these women at normal body mass indexes. Thus, BIA may be clinically useful for demonstrating sarcopenic obesity, but additional studies are needed to determine the metabolic and clinical significance of sarcopenic obesity.

Leisure, home, and occupational physical activity and cardiovascular risk factors in postmenopausal women. The Postmenopausal Estrogens/Progestins Intervention (PEPI) Study

OBJECTIVE

To examine the associations between self-reported leisure, home, and occupational physical activity and selected cardiovascular risk factors.

METHODS

A cross-sectional analysis of baseline data from the Postmenopausal Estrogen/Progestins Intervention Trial was performed in 851 women aged 45 to 64 years. Outcomes were levels of high-density lipoprotein cholesterol, insulin (2 hours after challenge), fibrinogen, systolic blood pressure. Race-stratified models were adjusted for age, smoking, alcohol, and previous noncontraceptive estrogen use. Models were also run with body mass index as an additional covariate.

RESULTS

In white women, leisure physical activity was positively associated with levels of high-density lipoprotein cholesterol (P = .001) and inversely associated with levels of insulin (P = .04) and fibrinogen (P = .02). Compared with high-density lipoprotein cholesterol levels in the inactive and light leisure physical activity groups, moderate (P < .001) and heavy (P = .004) leisure activities were associated with higher high-density lipoprotein cholesterol levels. High-density lipoprotein cholesterol levels in the heavy leisure physical activity group were significantly higher than those in the moderate group (P = .01). Compared with lesser levels of leisure physical activity, significantly lower mean values of fibrinogen (P = .02) and insulin (P = .01) were associated with the highest-intensity leisure physical activity. Home physical activity was positively related to high-density lipoprotein cholesterol level (P = .01); relative to lower levels of home physical activity, the heavy home physical activity group demonstrated significantly higher mean high-density lipoprotein cholesterol levels. The effects of leisure and home physical activities were independent of each other. systolic blood pressure did not vary by leisure, occupational, or home physical activity.

CONCLUSION

The unique relationships between type of physical activity and cardiac risk factors underscore the necessity of including multiple domains of activity in epidemiologic studies of epidemiologic studies of physical activity in women.

Late physical and functional effects of osteoporotic fracture in women: the Rancho Bernardo Study

OBJECTIVE

To examine the associations between osteoporotic fractures and difficulty performing selected physical and functional activities.

DESIGN

Cross sectional analysis of a cohort study.

SETTING

Geographically defined cohort located in Rancho Bernardo, California.

PARTICIPANTS

Community-dwelling women aged 55 and older who participated in a study of osteoporosis between 1988-1991. Eighty percent of eligible women participated in the study.

MAIN OUTCOME MEASURES

Self-reported difficulty performing seven physical activities and four functional tasks.

RESULTS

The mean age of the 1010 women was 72.6 years. A total of 160 first minimal trauma fractures occurred between 1972 and 1991, including 62 wrist, 29 rib, 25 hip, and 23 spine fractures. The mean time since fracture was 6.7 years (range, 1 to 17 years). In multiply adjusted analyses, having experienced any osteoporotic fracture was significantly associated with a 1.7 to 3.0-fold increase in difficulty bending, lifting, reaching, walking, climbing stairs, and descending stairs. Any fracture was significantly associated with 1.9 to 6.7 times more difficulty in dressing, cooking, shopping, and performing heavy housework. Compared with the relative odds of physical limitation associated with any osteoporotic fracture, hip fractures were more strongly associated with difficulty walking (OR 3.6) and descending stairs (OR 4.1), whereas spine fractures demonstrated a stronger association with difficulty bending (OR 3.1), lifting (OR 3.4), and descending stairs (OR 4.2).

CONCLUSIONS

Among older women, remote osteoporotic fracture at any site is associated with an approximate doubling of the risk of physical limitations and an even higher risk of functional limitations. Although this cross-sectional analysis cannot secure the direction of the association, the specificity of the effect of particular fractures on discrete activities supports causality.

Lifetime leisure exercise and osteoporosis. The Rancho Bernardo study

Between 1988 and 1991, the relation between leisure time physical activity, bone mineral density (BMD), and osteoporotic fracture was evaluated in a cohort of community-dwelling California adults (1,014 women and 689 men) with a mean age of 73 years. By means of a modified Paffenbarger questionnaire, participants were asked to report exercise from the past year and to recall their level of exercise during three other periods: the teenage years, age 30 years, and age 50 years. The survey asked the number of times strenuous (e.g., jogging), moderate (e.g., fast walking), or mild (e.g., golfing) exercise was undertaken in an average week. A summary score was constructed to represent lifetime exercise. Analysis of the exercise-fracture and exercise-BMD associations were performed using logistic and linear regression analyses, respectively. Linear regression models were controlled for age, body mass index, sex, diagnosis of arthritis, dietary calcium intake, and use of cigarettes, alcohol, thiazides, and estrogen (women only). No association between current or former exercise and BMD at the radius, wrist, or spine was found. A positive association between current exercise and BMD was found at the total hip (p = 0.001) and at each hip component--greater trochanter (p = 0.02), intertrochanter (p = 0.001), and femoral neck (p = 0.02). Mean hip bone densities of strenuous (p = 0.004) and moderate (p = 0.004) current exercisers were higher than those of mild or less than mild exercisers. Lifetime exercise was also positively associated with BMD of the total hip (p = 0.008) and hip components, and demonstrated a borderline-significant association (p = 0.06) with spine BMD. At the hip, each pairwise comparison between the highest and lowest tertiles of lifetime exercise showed a significant difference (p < or = 0.007). Exercise was unassociated with minimal trauma fracture occurring at any site between 1972 and 1991. These data suggest a protective effect of current and lifelong exercise on hip BMD, but not on osteoporotic fracture, in older men and women.

Infectious and catheter-related complications in pediatric patients treated with peritoneal dialysis at a single institution

Continuous ambulatory peritoneal dialysis (CAPD) and continuous cycling peritoneal dialysis (CCPD) are the predominant dialytic modalities for the majority of children while awaiting transplantation. Wide acceptability of peritoneal dialysis is hindered by infectious complications. A retrospective review of 367 pediatric patients treated with CAPD/CCPD for at least 3 months from September 1980 through December 1994 revealed that the peritonitis incidence ranged from 1.7 to 0.78 episodes per patient-year. No differences in peritonitis rates were observed between patients treated with CAPD or CCPD. Gram-positive organisms were responsible for the majority of peritonitis episodes. Age, sex, race, primary renal disease, presence of nephrotic syndrome, and serum albumin level were not associated risk factors. Longer time on treatment and diminished serum IgG level were associated with increased peritonitis incidence. Treatment was successfully completed at home in most cases. Almost half of the catheter losses were caused by Staphylococcus, Pseudomonas, and fungal peritonitis and tunnel/exit-site infections. Infectious complications are still the major causes of morbidity and treatment failure in patients treated with CAPD/CCPD. Thus, controlled studies are needed to assess methods for prevention or improvement of peritonitis rates in this patient population.

Dietary sodium and bone mineral density: results of a 16-year follow-up study

BACKGROUND AND PURPOSE

It has been proposed that high dietary sodium intake, resulting in a sodium-mediated increase in renal calcium excretion, is a risk factor for osteoporosis. To evaluate the relationship between dietary sodium intake and bone mineral density (BMD), a prospective study of the Rancho Bernardo cohort was performed.

METHOD

A 24-hour diet recall was done for the period 1973 through 1975; follow-up bone mineral density of the ultradistal radius, midradius, total hip, and spine was measured between 1988 and 1991. Covariates were ascertained by self-report and examination at baseline. Multivariable analysis of the sodium-BMD association was performed using gender and menopause-specific linear regressions.

RESULTS

All subjects were white. At the bone evaluation, there were 258 women (average age 73.3 years) and 169 men (average age 72.4 years). In both men and women, higher levels of sodium intake were strongly associated with higher levels of calcium intake and total calories. Body mass index increased with sodium quartile in women, while a modest negative association was seen in men. In women, after age adjustment, positive associations between dietary sodium and bone density were found at the ultradistal radius (beta = 0.01, P = 0.03) and the total hip (beta = 0.019, P = 0.02). BMD increased by 0.01 to 0.02 g/cm2 per gram increase in sodium ingested. After adjustment for estrogen use, body mass, dietary calcium, alcohol, and total calories, these effects were no longer significant. Similar patterns were seen in pre- and postmenopausal women. In men, age and multivariate-adjusted BMD increased with higher sodium intake at the ultradistal radius only (beta = 0.013, P = 0.05). Stratification by gender-specific median calcium level did not significantly effect the results.

CONCLUSIONS

After control for confounders, a small, statistically significant protective effect of sodium was found at the ultradistal radius in men only. At other sites in women and men, no effect of sodium on BMD was apparent in the multivariable models. These results do not support a detrimental effect of dietary sodium on bone mineral density. Rather, the findings suggest that sodium intake, in the range measured, is not a major osteoporosis risk factor.

Human islet isolation in 104 consecutive cases. Factors affecting isolation success

One of the major steps toward successful islet transplantation for the treatment of type diabetes is to obtain islets of sufficient number and viability. Using a standardized method of isolating islets, the goal of this study was to analyze the factors influencing the outcome of islet isolation. A total of 104 cadaveric human pancreata were processed for islets by the same team. Data from the islet-processing charts were reviewed retrospectively. The two endpoints were the recovery of islets, viable after 2 days of culture (group V = viable, group NV = nonviable) and the islet yield. Viable islets were recovered in 61% of cases (n = 63). Minimal blood glucose recorded during hospitalization was very significantly lower in group V (124 +/- 5 vs. 148 +/- 9, P = 0.01). Lack of significant medical history in the donor was associated with better viability as compared with various donor predispositions (chi-2 4.21, P = 0.04). Cold ischemia time (8.1 +/- 0.5 hr in group V vs. 9.8 +/- 0.9 hr in group NV, P = 0.07) and collagenase lot (5 lots tested, chi-2 13.1, P = 0.01) also affected the recovery of viable islets. Hospital time was shorter in group V (65.3 +/- 6.8 vs. 80.9 +/- 17.9 hr, P = 0.35). Multivariate logistic regression analyses of viable islet recovery identified minimal blood glucose (P = 0.03) and collagenase lot (P = 0.06) as the most significant risk factors. However, the best multivariate predictive model--which includes blood glucose, collagenase lot, donor age and surgical procurement team--correctly predicted 66.2% of cases only. Multivariate analysis of final islet yield designed hospitalization length, cardiorespiratory arrest, surgical procurement team, and collagenase lot as the best predictors. These data obtained in a large series of pancreata emphasized several donor and technical factors that should target the attention of islet transplant researchers in order to improve islet yield and viability.

Influence of marginal opening on microleakage of cemented artificial crowns

This study investigated the relationship between marginal opening and microleakage. Standardized preparations were made on intact human premolars, and copings were cast in a base metal alloy by use of conventional techniques. The castings were randomly assigned to the following luting agent groups: zinc phosphate cement, polycarboxylate cement, glass ionomer cement, phosphate ester composite resin, and a composite resin with a NPG-GMA dentinal bonding agent and were cemented in a standardized manner. The marginal openings between teeth and castings were measured, and microleakage was determined at the same points. Within the confines of the in vitro model used, no significant correlation between marginal opening and microleakage was established for either pooled data or individual luting agent groups.

Linkage analysis of DRD2, a marker linked to the ataxia-telangiectasia gene, in 64 families with premenopausal bilateral breast cancer

Recent reports suggest that subjects who are heterozygous for the ataxia-telangiectasia gene are at increased risk of breast cancer. We conducted linkage analyses of 64 families with premenopausal bilateral breast cancer using DRD2, a marker linked to the ataxia-telangiectasia locus at 11q22-23. We assumed a model with dominant transmission of breast cancer. Lod scores summed over all families provided strong evidence against tight linkage (e.g., a lod score of -6.08 at theta = 0.00001), although a single family provides suggestive evidence of tight linkage to DRD2. Evidence against linkage to 11q was strongest among families that may involve the BRCA1 breast cancer susceptibility gene on 17q21. However, we did not observe evidence of linkage to 11q among the remaining subgroup with neither a family history of ovarian cancer nor the appearance of linkage to 17q21.

A linkage analysis of D17S74 (CMM86) in thirty-five families with premenopausal bilateral breast cancer

We report here results of a linkage analysis of a marker in 35 families in which the proband had premenopausal bilateral breast cancer. This group is of particular interest given their high family risk and the question of etiological heterogeneity. Probands were ascertained from cancer registries in Los Angeles County and Connecticut and major hospitals in Montréal and Québec. Assuming no residual heterogeneity and summing lod scores over all families, we obtained strong evidence against tight linkage (e.g., lod score at theta = 0.000001 is -3.39). To address the issue of heterogeneity, we performed admixture and predivided sample analyses. Using an admixture model we were able to reject the hypothesis of no linkage versus that of linkage with homogeneity (P = 0.045). However, we were unable to reject the hypothesis of no linkage versus linkage with heterogeneity (P = 0.119) or to distinguish between linkage with homogeneity and linkage with heterogeneity (P = 0.500). Predivided sample analyses based upon age of onset, pathological characteristics, time between diagnoses of the breast cancers in each bilateral proband, and the span of ages at diagnoses within a family did not discriminate between apparently linked and unlinked families.

Open-eye corneal swelling secondary to hydrogel contact lens wear

Three hydrogel contact lenses of measured oxygen transmissibility (Dk/L = 20, 12, and 6 x 10(-9) cm ml O2/s ml mm Hg, respectively) were used to induce central corneal swelling as measured by optical pachometry in five human subjects under open-eye conditions (8 h wear). Both contact lenses with higher Dk/L values induced mean central corneal swelling of about 1.5%. The lower Dk/L lens induced a mean central corneal swelling of 2.2%. However, statistical analysis of the differences in central corneal swelling between the lens-wearing and the control eyes indicates that swelling induced by the higher Dk/L lenses is not identical, and indicates that even a Dk/L of 20 x 10(-9) is insufficient to reduce corneal swelling to zero. This suggests that the "critical oxygen tension" (COT) could be in excess of 20 to 40 mm Hg, but not necessarily as high as 70 mm Hg.