2,070,752 research outputs found
Preeclampsia risk, maternal 25-hydroxyvitamin D concentration, and variation in vitamin D metabolism pathway genes
No full textOBJECTIVE: Our objectives were to study the relationships between 25-hydroxyvitamin D (25(OH)D) and preeclampsia risk, maternal genetic variation in 3 vitamin D metabolism genes (GC, CYP27B1, VDR) and preeclampsia risk, and variation in the same genes and 25(OH)D. METHODS: We used two racially diverse pregnancy cohorts (EVITA and Collaborative Perinatal Project (CPP)) to achieve these objectives. We estimated the association between log-transformed 25(OH)D and preeclampsia risk in EVITA by using log-binomial regression with restricted cubic splines. In EVITA and CPP, we used multivariable logistic and linear regression models to estimate the associations between allelic variation and preeclampsia risk, and genotype and log-transformed 25(OH)D, respectively. Meta-analyses were conducted to calculate estimates of association between and within cohorts. RESULTS: Dose-response associations of 25(OH)D were observed for both severe and mild preeclampsia. Trends of associations were observed in genetic variation and preeclampsia risk. Compared with major allele carriers, Black mothers in EVITA who carried the minor allele for rs11732451 GC single nucleotide polymorphism (SNP) and 2 VDR SNPs (rs4340112, rs10459217) had increased odds of preeclampsia, while the odds were lowered for those who carried the minor allele for 1 GC SNP (rs1099028) and 2 VDR SNPs(rs757344, rs12721364). In the meta-analysis, two VDR SNPs (rs886441 and rs2853561) had trends of decreased odds of preeclampsia for all Black mothers. For the 25(OH)D analysis, statistically significant associations were observed. Compared with those with major allele genotypes, mothers with minor allele genotypes of rs1844885 (GC) and rs11168275 (VDR) had increased 25(OH)D and of rs11732451 (GC) had lowered 25(OH)D. In the meta-analysis on all Black mothers, rs1844885 (GC) was associated with increased 25(OH)D while there was a trend of decreased 25(OH)D for rs10877016 (CYP27B1). CONCLUSIONS: Low 25(OH)D may be enough to reduce risk of preeclampsia. If our findings are confirmed in a replication study, genetic variation may be an independent risk factor for maternal 25(OH)D, making the findings of this research relevant to public health
Evaluating the effectiveness of state R&D tax credits
No full textThis paper aimed to analyze the effectiveness of state R&D tax credit programs in the context of R&D-relevant policies and regional economic development policies. Although there were extensive theoretical recommendations for promoting private R&D, and state R&D tax credit programs have been one of the most popular regional economic development programs, only few evaluations of state R&D tax credit programs have been conducted. Inspired by this lack of previous study, this study provided an empirical finding for the effectiveness of these programs by applying a quasi-experimental approach, which means conducting experiments without randomness, for comparing states with tax credits and states with no credits.For dealing with the embedded non-randomness, plausible other explanations that weaken the causal relationship between the programs and the effects were examined and ruled out as much as possible. Rival hypotheses were selected using different tax and government policies, overall business and R&D-specific environments, and firm characteristics. They were eliminated by constructing valid control groups, using the difference-in-differences and matching methods, selecting covariates and matching variables as observable variables, and absorbing year-specific fixed effects and cross-sectional-fixed effects as unobservable variables. The decision was made based on multiple estimates and multiple datasets. The research analyzed two sets of industries: the all industry group and high-technology industy. The major findings are : 1) state R&D tax credits positively affect the increase in R&D spending and increase in employment; 2) positive effects on R&D spending are widespread across the all industry group while positive effects on employment are limited to high-technology industry overall; 3) positive effects on R&D spending are also spread out to different sized firms in both the all industry group and high-technology industry; and 4) positive effects on employment are found mainly in large firms in both the all industry group and high-technology industry.The above findings support the utilization of state R&D tax credits. As an indirect intervention, state R&D tax credit programs can increase productivity and encourage innovation by generating additional private R&D activities. State R&D tax credit programs can also make a positive contribution to regional economic growth through the growth of R&D-relevant and high-technology industries
The role of vitamin D in type 1 diabetes complications: a cross sectional analysis of the Pittsburgh EDC study
No full textBackground: It has been postulated that vitamin D deficiency may be associated with diabetic complications. A comprehensive analysis of microvascular and macrovascular complications, however, has not been conducted in patients with type 1 diabetes. Hence, we investigated the associations between vitamin D levels and the prevalence of microalbuminuria, overt nephropathy, impaired endothelial function, end stage renal failure, confirmed distal symmetric polyneuropathy, coronary artery disease and lower extremity arterial disease in individuals with type 1 diabetes.\ud
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Methods: We measured circulating 25(OH)D and 25(OH)D3 in 214 individuals with type 1 diabetes who participated in the 25 year clinical visit of the Pittsburgh Epidemiology of Diabetes Complications study of childhood onset type 1 diabetes (n=214, mean age = 51 years and median diabetes duration = 42 years). Cross-sectional associations of 25(OH)D and 25(OH)D3 with diabetic complications were assessed with multivariable logistic regression adjusted for diabetes duration, sex, BMI, season of visit, HbA1c, insulin dose per body weight, hypertension, HDL and non-HDL cholesterol, WBC count, estimated glomerular filtration rate and albumin to creatinine ratio, as appropriate.\ud
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Results: Fully adjusted models revealed that each 1 ng/ml increase in 25(OH)D was associated with 3% to 6% lower odds of microalbuminuria (OR=0.97, 95% CI=0.94, 0.99), impaired eGFR (OR=0.96, 95% CI=0.93, 0.99) and confirmed distal symmetric polyneuropathy (OR=0.94, 95% CI=0.90, 0.98). Similar results were found for 25(OH)D3. These vitamin D metabolites were not independently associated with overt nephropathy, end stage renal failure, coronary heart disease or lower extremity arterial disease.\ud
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Conclusions: In this cohort of middle-aged adults with type 1 diabetes, both higher 25(OH)D and 25(OH)D3 were related with a lower prevalence of early diabetic kidney disease and diabetic neuropathy, but not with advanced renal disease and macrovascular disease. For the interest of public health, it would be imperative to determine whether vitamin D levels can further predict the risk of developing these diabetic complications
Vitamin D Testing Practices in Collegiate Cross Country and Track and Field Athletes
No full textVitamin D insufficiency and deficiency has become problematic within the global population. Low levels of Vitamin D may have significant impacts on bone health and the musculoskeletal system, key factors in athletic performance. Recently, Vitamin D testing has gained popularity amongst athletic populations, but there is little research in cross country and track and field (XC and TF) collegiate athletes. The purpose of this study was to investigate the Vitamin D testing practices of NCAA sponsored XC and TF programs. Fifty-five Certified Athletic Trainers (ATs) participated in the study (43 XC and TF ATs, 12 non-XC and TF ATs). The responses of XC and TF ATs were analyzed separately and compared by region of the U.S. and NCAA Division classification. Few participants (6/30) identified their institution as having a Vitamin D testing policy in place. The six participants indicated that red flags and health history are the primary indications for Vitamin D testing while preventative screening occurs at half of the Division I institutions. There was little consensus regarding adequate Vitamin D levels and number of Vitamin D tests per year. Although, 70.6% of Division I XC and TF ATs support Vitamin D testing in their athletes while 66.7% of Divisions II and III ATs did not. In addition to testing practices, this study gathered data regarding indoor training duration and bone stress injuries for XC and TF collegiate athletes. There was no significant association between indoor training duration and region of the U.S. for XC athletes, however, there was a statistically significant association for TF athletes (p = 0.016, 0.050). Using the injury data provided, an injury incidence and frequency was calculated of which women’s XC had the highest rates (11.9, 14.1), followed by women’s TF (6.3, 9.2), men’s XC (5.4, 7.6), and men’s TF (4.1, 4.9). A major limitation of the present study was the small sample size, however, future research utilizing an increased sample size may produce different or more statistically significant results. Overall, continued education and research regarding the importance of Vitamin D and athletic performance is necessary to create universal testing policies in collegiate athletics
Vitamin D, Tissue Resistance, Bone Mineral Density and Breast Cancer Risk
No full textEtiologic factors such as vitamin D and estrogen are potentially related to breast cancer development, although details of their mechanisms are not completely understood. We prospectively investigated correlates of breast cancer risk among postmenopausal women in the Study of Osteoporotic Fractures (SOF). First, we undertook a case-cohort study to test the hypothesis that low serum 25-hydroxyvitamin D [25(OH)D] will be associated with an increased risk of ER+ breast cancer (N=502). Low 25(OH)D levels were not associated with an increased risk of breast cancer and do not support an association between 25(OH)D and ER+ breast cancer development. Second, we utilized fractional calcium absorption (FCA) as a marker of tissue resistance to vitamin D to test the hypothesis that low FCA will be associated with an increased risk of breast cancer (N=5035). To the contrary, over a mean 9.6 years, increasing rates of FCA were associated with a higher risk of invasive breast cancer. A stronger positive relationship was noted among women with low dietary calcium intake. The findings support a modestly increased risk of breast cancer with higher FCA rates particularly among those who have low calcium intake. Finally, we examined the long-term association of an initial bone mineral density (BMD) measure and change in BMD (annual percent change assessed 3.5 years later) on breast cancer risk (N=5385). Furthermore, we tested the hypothesis that the risk associated with an initial BMD measure would be strengthened by the addition of the change variable. Over a mean 9.5 years, there was no association between increasing levels of BMD, change in BMD, or a combined model and breast cancer. The effect of BMD was found to be dependent upon family history of breast cancer. Among women with a positive family history, high BMD was associated with a 3-fold higher risk of breast cancer compared to low BMD. Through our investigations of two etiologic factors and their association with breast cancer development, we have enhanced our knowledge regarding the interdependence of vitamin D, calcium, and estrogen. These findings may lead to improved opportunities for prevention and early detection and are of significant public health relevance
THE EFFECT OF A 12-MONTH WEIGHT LOSS INTERVENTION ON VITAMIN D STATUS IN SEVERELY OBESE CAUCASIANS AND AFRICAN AMERICAN ADULTS
No full textVitamin D deficiency is a potential risk factor for several chronic conditions, including cardiovascular disease, diabetes and immune disorders. Several studies have found an association between Vitamin D deficiency and obesity, yet it is unclear whether Vitamin D contributes to obesity, or obesity itself causes Vitamin D deficiency. The purpose of this study is to determine the relationship between obesity and Vitamin D status and to examine the effects of weight loss and physical activity on Vitamin D status in severely obese Caucasians and African Americans. 50 class II and class III obese women participated in a 12-month diet and exercise intervention. Vitamin D status was examined at baseline, 6 and 12 months to determine the relationship between Vitamin D and weight loss, fat loss, race and physical activity. At baseline, both the Class I and Class III obese subjects were considered Vitamin D insufficient (20-30 ng/mL). The Class II subjects were considered deficient (30 ng/mL). Caucasians in the Class I and III obese groups had significantly higher Vitamin D than African Americans. Vitamin D increased significantly following 6 months of weight loss. There was no significant relationship between change in Vitamin D and change in body weight or body fat. Vitamin D decreased at 12 months despite a period of weight maintenance yet remained significantly greater than baseline. Meal replacement shakes containing Vitamin D were taken twice per day from baseline to 6 months and once per day from 6-12 months, contributing to the increase in Vitamin D at 6 months and 12 months. Throughout the intervention, Vitamin D status was significantly greater in Caucasians than African Americans. There was no relationship between Vitamin D status and physical activity at 6 or 12 months. The results of this study confirm that Vitamin D deficiency or insufficiency is related to degree of adiposity and is more prevalent in African Americans than Caucasians. Moreover, a dietary weight loss intervention significantly increased Vitamin D in severely obese women, indicating that lower Vitamin D in obesity is amenable to weight loss intervention
Variants in the vitamin D pathway, serum levels of vitamin D, and estrogen receptor negative breast cancer among African-American women: A case-control study
No full textIntroduction: American women of African ancestry (AA) are more likely than European Americans (EA) to have estrogen receptor (ER)-negative breast cancer. 25-hydroxyvitamin D (25OHD) is low in AAs, and was associated with ER-negative tumors in EAs. We hypothesized that racial differences in 25OHD levels, as well as in inherited genetic variations, may contribute, in part, to the differences in tumor characteristics.Methods: In a case (n = 928)-control (n = 843) study of breast cancer in AA and EA women, we measured serum 25OHD levels in controls and tested associations between risk and tag single nucleotide polymorphisms (SNPs) in VDR, CYP24A1 and CYP27B1, particularly by ER status.Results: More AAs had severe vitamin D deficiency ( twofold increased risk of ER-negative breast cancer among AAs (OR = 2.62, 95% CI = 1.38-4.98), but had no effect in EAs. rs2209314 decreased risk among EAs (OR = 0.38, 95% CI = 0.20-0.73), with no associations in AAs. The increased risk of ER-negative breast cancer in AAs compared to EAs was reduced and became non-significant (OR = 1.20, 95% CI = 0.80-1.79) after adjusting for these two CYP24A1 SNPs.Conclusions: These data suggest that genetic variants in the vitamin D pathway may be related to the higher prevalence of ER-negative breast cancer in AA women. © 2012 Yao et al.; licensee BioMed Central Ltd
n-3 and n-6 Polyunsaturated Fatty Acids and Vitamin D related to Subclinical Atherosclerois in the ERA-Jump Study
No full textCardiovascular disease is of public health significance due to its highest rates of mortality. Atherosclerotic cardiovascular events can often result in fatal or disabling non-fatal events. More than half of CHD fatal events do not show earlier symptoms. Early identification of subclinical atherosclerosis and establishment of preventive control are important to reduce CHD mortality and morbidity. The present study aimed to examine: 1) whether n-6 fatty acids are inversely associated with plasminogen activator inhibitor-1 (PAI-1) and fibrinogen; 2) whether vitamin D deficiency is associated with subclinical atherosclerosis; and 3) whether Japanese men have lower incidence or progression of CAC than Caucasian men, and further if marine n-3 fatty acids are inversely associated with incidence or progression of CAC. To test these aims, the Electron-Beam Tomography, Risk Factor Assessment among Japanese and U.S. Men in Post-World War II Birth Cohort (ERA-JUMP) study was utilized.The findings were: 1) in a population-based cross-sectional-sample of 915 men aged 40-49, serum n-6 fatty acids were inversely and significantly associated with PAI-1 but not with fibrinogen; 2) in 295 middle-aged men of a population-based cross-sectional sample, Japanese men showed lower levels of serum vitamin D, despite their habitual fish intake as a major dietary intake, than Caucasian or Japanese-American men. Further, vitamin D deficiency was not associated with subclinical atherosclerosis as measured by intima-media thickness (IMT) and CAC, except for significant associations on IMT in a univariate model among Caucasian men, and on CAC in both univariate and multivariate models among Japanese-American men; and 3) in the follow-up study of 472 men, Japanese men had a significantly lower incidence and progression of CAC than Caucasian men. Japanese men showed significant risk reduction on incident CAC associated with marine n-3 PUFA. However, Japanese and Caucasian men showed no significant associations of marine n-3 PUFA on the progression of CAC. Future studies to examine the causal associations as well as underlying mechanisms are warranted. From the public health importance, these findings extend our understanding of n-3 and n-6 polyunsaturated fatty acids and vitamin D related to subclinical atherosclerosis as well as help to establish public health guidelines
PROBABILITY-BASED SIMULATION OF 2-D VELOCITY DISTRIBUTION AND DISCHARGE ESTIMATION IN OPEN CHANNEL FLOW
No full textA probability-based method is presented that can be used to simulate 2-D velocity distribution in rectangular open channels and to estimate the flow discharge. The method is based on Chiu's velocity distribution equation. A technique for estimating a parameter of 2-D velocity equation has been developed, by which the 2-D velocity distribution in rectangular open channels can be simulated by using one or several velocity samples, or even without using any velocity data. The present study also developed an efficient method of discharge estimation in rivers, which is applicable regardless of whether flow is steady or unsteady. It only requires a quick velocity sampling. The relation between the surface velocity and the vertical mean velocity has been studied. It can be used for developing a non-contact method of discharge measurement.Under the same framework of analysis, a new slope-area method has been developed to determine the flow discharge. It can reduce errors due to the uncertainties in Manning's n and the energy coefficient that exist in the widely-used slope-area method
Evaluating the effect of medicare shared savings program accountable care organizations on part d pharmaceutical spending and use
No full textMedicare Shared Savings Program (MSSP) is one major model of the Accountable Care Organizations (ACOs) offered by Medicare to better manage health cost and improve the quality of health services. The payment MSSP ACOs receive from Medicare is directly related to its Medicare Part A and B spending and related health service quality. Currently Medicare Part D spending covering medication cost is not included in the calculation of MSSP ACOs shared savings and risks. Since improvement of medication coverage and drug adherence have been shown to decrease other medical cost such as hospital and outpatient care, ACO providers may be incentivized to increase the shared savings by lowering Part A and B spending through increasing Part D drug prescription. This study evaluated the effect of MSSP ACOs on the Part D spending and utilization with a quasi-natural difference-in-differences model. We investigated the change in outcome variables between pre- and post-ACO enrollment during 2010-2013 by comparing MSSP ACOs and non-ACO Medicare providers.
We found that when individually compared with non-ACO providers, Part D spending and use mildly increased after providers enrolled in MSSP. However, the statistical significance of this effect disappeared after controlling for other ACO providers started their MSSP contracts at different times. To evaluate the c. Characteristics of those providers not considered in this study might also have an influence on Part D spending and thus a valid control group would need to be carefully chosen for future studies.
Public health significance: Understanding the ACO effects on Medicare Part D spending and utilization helps evaluate the success of ACOs to increase shared savings and to improve health quality compared with original management models in Medicare
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