Age Regression Coefficient Research Articles

Economic study of Binadhan-22 production in some selected areas of Bangladesh

This study was conducted in four districts of Bangladesh, namely Mymensingh, Bogura, Naogaon and Rangpur to estimate the profitability and factors affecting gross return of the variety. This study was based on primary data which were collected from 200 Binadhan-22 growing farmers. In the sampled areas data were collected through pre-designed interview schedule from January-February, 2023. Tabular, descriptive statistics and Cobb-Douglas production function model were used to fulfill the objectives. It was found that Binadhan-22 production is profitable. The average net return per hectare was Tk. 28876. The net return was highest in Rangpur (Tk. 32480/ha) followed by Naogaon (Tk. 28554/ha), Mymensingh (Tk. 27331/ha) and Bogura (Tk. 27139/ha), respectively. Benefit cost ratio was estimated at 1.39 and 2.04 on full cost and variable cost basis. Cobb-Douglas production function was chosen to determine the factor affecting gross return of Binadhan-22 production. All of the factors namely, human labour cost, power tiller cost, seed cost, fertilizer cost, irrigation cost, insecticides cost were statistically significant and positive. The regression coefficients for farming experience and agricultural training under all areas had negative but significant relationship at 5% and 10% level, respectively. The regression coefficient of age was positive and significant at 10% level. Under all areas, the regression coefficients of education and farm size were positive but not significant. Farmers faced some constraints in cultivating of the variety. The first ranked constraint was lack of availability of seeds (93%). Other constraints were lack of training (61%), lack of capital (38%) and lack of technical know-how (16%). In addition to helping farmers use a better combination of inputs that will create higher productivity and return, effective extension services may also assist farmers in cultivating rice in a way that will contribute to food security and self-sufficiency. Bangladesh J. Nuclear Agric, 38(1): 81-91, 2024

Profitability analysis of Binadhan-20 production in some selected areas of Bangladesh

This study was conducted to analyze the profitability of Binadhan-20 producing farmers in Mymensingh, Jamalpur and Rangpur districts of Bangladesh. This study was based on primary data which were collected from 150 Binadhan-20 producing farmers. In the sampled areas data were collected through pre-designed interview schedule from February-March, 2022 for achieving the purpose. In the study, costs and return analysis were done on both cash cost and full cost basis for estimating profitability. The cultivation of Binadhan-20 was profitable from the viewpoint of the farmers. The study found that Binadhan-20 production is profitable. The average net return per hectare was Tk. 29964. The net return was highest in Rangpur (Tk. 31735/ha) followed by Mymensingh (Tk. 30142/ha) and Jamalpur (Tk. 28015/ha), respectively. Benefit cost ratio was 1.41 and 2.02 on full cost and cash cost basis implying that the Binadhan-20 cultivation at farm level was profitable. Cobb-Douglas production function was chosen to determine the factor affecting gross return of Binadhan-20 production. All of the factors namely, human labour cost, power tiller cost, seed cost, fertilizer cost, irrigation cost, wedding cost and insecticides cost were statistically significant and positive. The regression coefficients for farming experience and agricultural training under all areas had negative but significant relationship at 5% and 10% level, respectively. The regression coefficient of age was positive and significant at 5% level. Under all areas, the regression coefficient of education and farm size was positive but not significant. The farmers in the study areas encountered some constraints to Binadhan-20 production. The first ranked constraint was unavailability of seeds in all areas (92%). Other constraints were lack of training (65%), lack of technical know-how (40%), natural calamities (36%), lack of capital (26%) and low education level of farmers (14%). The economic return of Binadhan-20 production encouraging to the farmer’s for more production. Bangladesh J. Nuclear Agric, 37(1): 81-90, 2023

Correlation between sagittal parameters and disability of patients with nonspecific chronic low back pain: a cross-sectional study of 435 subjects

BACKGROUND CONTEXTSagittal parameters are significantly correlated with health-related quality of life (HRQoL) in adult spinal deformity patients. Their association with HRQoL in patients with nonspecific chronic low back pain (NSCLBP) is unclear. PURPOSETo analyze the correlation between sagittal parameters and disability in NSCLBP patients. DESIGNA cross-sectional study. PATIENT SAMPLESubjects included 435 patients with NSCLBP divided into low disability and high disability groups. OUTCOME MEASURESFunction was measured using the Oswestry Disability Index (ODI). Pain intensity was measured using the Numeric Rating Scale (NRS) and HRQoL was measured using 36-item Short Form Health Survey (SF-36). METHODSSagittal parameters, demographic data, ODI, SF-36 eight-dimensional scores and NRS scores of patients with NSCLBP were collected. Taking ODI=20 as the cut-off value, patients were divided into low disability group (ODI≤20) and high disability group (ODI>20), and ODI were converted to Ranked ODI (RODI) accordingly. Univariate analysis of the correlation among age, gender, body mass index (BMI), sagittal parameters, RODI, SF-36 eight-dimensional scores, NRS scores were then conducted. The variables related to RODI were analyzed by logistic regression to discover their independent influence on RODI. p<.05 was considered to indicate statistical significance. RESULTSA total of 435 patients with NSCLBP were included. Univariate correlation analysis showed that the correlation coefficients between age, sacral slope-pelvic tilt (SS-PT), spinosacral angle (SSA) and RODI were (r=0.126, p<.01), (r=−0.115, p<.05), (r=−0.116, p<.05), respectively. The logistic regression analysis indicated that the regression coefficients of age and SSA were 0.030 (p=.001), −0.044 (p=.002), respectively, and the odds ratio and 95% confidence interval (CI) were 1.031 (1.012, 1.050), 0.957 (0.930, 0.985). CONCLUSIONSAge and SSA are independent factors for disability of NSCLBP. SSA can comprehensively reflect the sagittal balance of the spine of patients with NSCLBP. Decreased SSA represents poor sagittal balance, which will increase the disability of NSCLBP.

The Effect of Age And Work Period On Teaching Quality Of Economics Teachers At SMK N 1 Nainggolan Samosir T.P 2015/2016

The results of the analysis obtained for age (X1) on the teaching quality of economics teachers (Y) obtained tcount &gt; ttable, indicating that there is an influence of age on the teaching quality of economics teachers. The results of the analysis obtained for the effect of tenure (X2) on work quality (Y) obtained tcount &gt; ttable, indicating that there is an influence of tenure on the quality of teaching economics teachers. In the calculation of multiple linear regression, constant values are obtained, the regression coefficient for age (X1) s and the regression coefficient for years of service (X2) are equal to. To test the hypothesis of age and years of service simultaneously using the f test with a significance level of 95%, the value of Fcount &gt; Ftable is obtained, indicating that there is a simultaneous significant effect of age and years of service on the quality of teaching economics teachers.

Analysis of Involvement of Women in Food Crop Production in Hawul Local Government Area, Borno State, Nigeria.

This study was conducted to Analyse the Involvement of women in food crop production in Hawul Local Government Area, Borno State, Nigeria. 100 women food crop farmers were randomly selected for the study and a structured questionnaire was used to collect data from the respondents, which were analysed using descriptive statistics and regression analysis. The results revealed that most (37.0%) of the respondents belonged to the age group of 26-35 years. 50% married, 36% literate, and 37.0% have a small portion of farm land. The findings also revealed that 30.0% had 6-10 years farming experience, 40.0% believed insufficient farm land is their major problem. (53.0%) do not participate in land selection, but most (47.2%) participate in processing activities. The coefficient of multiple determinants R2 of 0.5337 indicated a high relevance of input in explaining the observed variation in food crop production. The regression coefficient of age, household size, education and farming experience are significant at 1% level of significance. It was concluded that women role in agricultural food crop production is at a subsistence level and are constrained by several factors. The study recommends that extension agency should link women farmers with sources of credit facilities, to enable them have access to capital that will help them purchase the needed farm inputs. Government should sensitize and encourage women to increase participation in land selection and storage activities for increase yield.

Effects of Anti-Diabetic Drugs on Fracture Risk: A Systematic Review and Network Meta-Analysis.

PurposeAvailable data on the effects of anti-diabetic drugs on fracture risk are contradictory. Therefore, our study aimed to analyze all available data on the effects of anti-diabetic drugs on fracture risk in type 2 diabetes mellitus (T2DM) patients.MethodsEmbase, Medline, ClinicalTrials.gov, and Cochrane CENTRAL were searched for relevant trials. All data analyses were performed with STATA (12.0) and R language (3.6.0). Risk ratio (RR) with its 95% confidence interval (CI) was calculated by combining data for the fracture effects of anti-diabetic drugs, including sodium–glucose co-transporter 2 (SGLT2) inhibitors, dipeptidyl peptidase-4 (DPP-4) inhibitors, glucagon-like peptide-1 (GLP-1) receptor agonists, meglitinides, α-glucosidase inhibitors, thiazolidinediones, biguanides, insulin, and sulfonylureas.ResultsOne hundred seventeen eligible randomized controlled trials (RCTs) with 221,364 participants were included in this study. Compared with placebo, trelagliptin (RR 3.51; 1.58–13.70) increased the risk of fracture, whereas albiglutide (RR 0.29; 0.04–0.93) and voglibose (RR 0.03; 0–0.11) decreased the risk of fracture. Other medications were comparable in terms of their effects on fracture risk, and no statistical significance was observed. In terms of fractures, voglibose (0.01%) may be the safest option, and trelagliptin (13.64%) may be the worst. Sensitivity analysis results were consistent with those of the main analysis. No statistically significant differences were observed in the regression coefficients of age (1.03; 0.32–2.1), follow-up duration (0.79; 0.27–1.64), and sex distribution (0.63; 0.15–1.56).ConclusionsWe found varied results on the association between the use of anti-diabetic drugs and fracture risk. Specifically, trelagliptin raised the risk of fracture, whereas voglibose and albiglutide showed benefit with statistical difference. Other drugs were comparable in terms of their effects on fracture risk. Some drugs (omarigliptin, sitagliptin, vildagliptin, saxagliptin, empagliflozin, ertugliflozin, rosiglitazone, pioglitazone, and nateglinide) may increase the risk of fracture, while others (such as dulaglutide, exenatide, liraglutide, semaglutide, lixisenatide, linagliptin, alogliptin, canagliflozin, dapagliflozin, glipizide, gliclazide, glibenclamide, glimepiride, metformin, and insulin) may show benefits. The risk of fracture was independent of age, sex distribution, and the duration of exposure to anti-diabetic drugs. When developing individualized treatment strategies, the clinical efficacy of anti-diabetic drugs must be weighed against their benefits and risks brought about by individual differences of patients.Systematic Review RegistrationThis Systematic Review was prospectively registered on the PROSPERO (https://www.crd.york.ac.uk/PROSPERO/, registration number CRD42020189464).

Research on the Influence of Managerial Characteristics on Accounting Conservatism in Public Coal Companies during the period of COVID-19

Objectives For a long time, scholars have been concerned about the impact of manager and team characteristics on corporate performance or corporate value, and the spread of COVID-19 forces us to consider the impact of manager characteristics on accounting conservatism. Methods This paper selects the financial data of 34 public coal companies from 2015 to 2019 as the research sample, establishes the measurement model of accounting conservatism based on Basu model to evaluate the accounting conservatism of public coal companies, and uses three regression models to study the impact of managers' age, education level and tenure on the accounting conservatism of companies. Results The results show that accounting conservatism is common in public coal companies, and the average value of C-score is greater than 0 for five consecutive years. Conclusions Furthermore, the empirical results show that the regression coefficients of age and tenure of managers are 0.0224 and 0.0035, respectively, which indicates that the age and tenure of managers have a positive impact on accounting conservatism. However, the level of education has no significant impact on the accounting conservatism of public coal companies, which depends on the particularity of production and management of public coal companies, and cannot completely deny the impact of education level on the conservatism.

The Trends of Medical Care Expenditure with Adjustment of Lifestyle Habits and Medication; 10-Year Retrospective Follow-Up Study.

In Japan, the prevention of lifestyle-related diseases is the most important issue for the optimization of medical expenditure. This study aimed to analyze the impact of lifestyle and medication status on medical expenditure. Health checkup data and medical expenditure records of a retrospective cohort of 1463 people aged between 40 and 65 years old who underwent specific health checks at least three times between 2008 and 2017 were analyzed. Regression analysis was performed with medical expenditure as the dependent variable and age, gender, waist ratio, medication status, and lifestyle habits as independent variables using a Tobit model. Focusing on the factors that increase medical expenditure, the regression coefficients of age, medication status, weight gain of 10 kg or more since the age of 20, and walking more than 1 h per day were 0.048 (95% CI 0.04 to 0.06), 1.020 (95% CI 0.88 to 1.16), 0.210 (95% CI 0.06 to 0.36), and −0.208 (95% CI −0.35 to −0.07), respectively. The estimate of 5-year cumulative medical expenditure showed that those with walking habits without medication had the lowest medical expenditure. The result of this study suggests that walking more than 1 h a day may lower health expenditure in the general population.

Basic Motor Skills of Children With Down Syndrome: Creating a Motor Growth Curve.

To create a motor growth curve based on the Test of Basic Motor Skills for Children with Down Syndrome (BMS) and estimate the age of achieving BMS milestones. A multilevel exponential model was applied to create a motor growth curve based on BMS data from 119 children with Down syndrome (DS) aged 2 months to 5 years. Logistic regression was applied to estimate the 50% probability of achieving BMS milestones. The BMS growth curve had the largest increase during infancy with smaller increases as children approached the predicted maximum score. The age at which children with DS have a 50% probability of achieving the milestone sitting was 22 months, for crawling 25 months, and for walking 38 months. The creation of a BMS growth curve provides a standardization of the gross motor development of children with DS. Physical therapists then may monitor a child's individual progress and improve clinical decisions.

A contingent valuation approach to estimating willingness to pay for fish solar drying technology: Case of western shore of Lake Malawi

For many years, open sun drying (OSD) has been the common way of preserving fish among the fishing households in Malawi. The main limitations of this technique have been increased fish quality deterioration and microbial contamination. Two fish solar dryers (FSD) were constructed under the SEEDFISH project along the Western Shore of Lake Malawi (WSLM) as a way of minimizing the effects of using OSD and provide a better way of drying fish in the area. The FSD though adopted, the fishing households have been seeking alternatives for its sustenance. This study estimates the households’ willingness to pay (WTP) and their influencing factors while using contingent valuation (CV) approaches. A wide range of data collection methods (exploratory surveys, focus group discussions, key informant interviews, and field observations) was employed. A total of 200 fishing households were randomly interviewed. The results showed that 144 (72.4%) of the respondents were willing to pay because the FSD was seen as a way of mitigating the climate change impact, improving livelihoods, and reducing post-harvest losses. The mean annual aggregate WTP amount was estimated at MK3,648,750 (US$4,865). Those households (27.6%) not willing to pay argued that they had a low level of income while others could not see any value of the FSD. The regression coefficients of age and gender of household head (GHH) were negative (β =-6.02 andWald of 5.34, β = -6.92, Wald of 2.01) and significant (p<0.05) suggesting that young people were more WTP than their counterpart. Males also coded as 0 were more willing to pay than females. On the other hand, household literacy level (HLL), household involved in fish processing (HIVFP), household social trust (HST), household institutional trust (HIT), household level of income (HLI), household experienced fish post-harvest losses (HEFPL), household access to extension services (HAE) and household social network (HSN) were positive (β = 2.97, Wald of 7.11, β = 6.37 andWald of 5.41, β = 3.03 and Wald of 6, β = 11.2, Wald 9.02, β = 2.42, Wald of 8, β = 0.93, Wald of 4,81 and β = 2.50, Wald 2.10) and significant (p<0.05) suggesting that those HIVFP, had high HLL, HLI, HST, HIT, HSN and HEFPL were more willing to pay than their counterpart. These findings provide comprehensive baseline data for local government and communities in the development of more effective and holistic approaches to improving communities’ climate change resilience. Key words: Contingent valuation, Fish solar dryer, Lake Malawi, Willingness to pay

P1575STUDY ON THE CLINICAL CHARACTERISTICS OF PROTEIN-ENERGY WASTING AND PERSISTENCY RATE OF EXERCISE TRAINING IN PATIENTS ON HEMODIALYSIS

Abstract Background and Aims Frailty is common among elderly patients on hemodialysis (HD), and is associated with protein-energy wasting (PEW), sarcopenia and dynapenia. Frailty and PEW are associated with impaired physical performance, poor quality of life (QOL), disability and reduced survival. Prevention and treatment of these conditions often requires a multifaceted approach. In this study, we examine the effect of PEW and the persistency rate of exercise training among elderly patients on HD. Method Study (1): The HD program included 722 patients (515 males, 207 females), who underwent 4-h HD sessions, were assigned to 2 groups (PEW group and non-PEW group). We collected the biochemical data and investigated dry weight (DW: kg), duration of HD (months), body mass index (BMI), % creatinine generation rate (%CGR), and normalized protein catabolic rate (nPCR). Study (2): This was retrospective, multi-center study and included 53 patients on HD (25 males, 28 females; mean age: 72.5±9.1 years, BMI; 22.5±3.5 kg/m2). The HD patients were non-randomly assigned to an exercise training group during HD (E group) or to an exercise training group at home (H group). The E group used medicine balls during the first 2 h of the HD sessions. The H group strengthened the quadriceps and the gastrocnemius muscles by half-squatting by raising the heel or single-leg standing, respectively. We collected the main biochemical data after 6 months of exercise training and measured the left and right knee extension strength using a hand-held dynamometer. We investigated the persistency rate of exercise training and its factors. Results Study (1): The mean age of the patients was 67.0±13.1 years; the mean HD duration was 83.2±83.6 months. PEW and non-PEW groups consisted of 162 HD patients (22.4%; 112 males, 50 females, HD duration 76.5±91.5 months) and 560 HD patients (77.6%; 403 males, 157 females, HD duration 85.1±78.4 months), respectively. The mean age of the PEW group was significantly higher than that of the non-PEW group (71.0±12.5 vs 66.0±13.1 years; P&amp;lt;0.01). The mean DW (54.6±13.8 vs 60.4±13.4 kg, P&amp;lt;0.01), mean serum albumin (3.3±0.3 vs 3.5±0.4 g/dL, P&amp;lt;0.01), mean BMI (20.4±4.3 vs 22.5±3.9 kg/m2, P&amp;lt;0.01), mean %CGR (72.0±24.0 vs 96.7±22.5 %, P&amp;lt;0.01), and mean nPCR (0.75±0.16 vs 0.91±0.14 g/kg/day, P&amp;lt;0.01) of the PEW group were significantly lower than those of the non-PEW group. By multiple logistic regression analysis, the partial regression coefficient of age was 0.28, and the odds ratio was 1.029. Study (2): After 3 months, the persistency rate of exercise training was 77.4% (41 HD patients). After 6 months, the persistency rate of exercise training was 50.3% (27 HD patients). The factors of dropout of exercise training were loss of motivation (42.9%), leg pain (21.4%), physical deconditioning (14.3%), change in blood pressure (7.1%), hospitalization (7.1%), and admission to a nursing facility (7.1%). In the H group, the muscle strength of the knee extensors significantly increased from 25.7±7.1 kgf (baseline) to 28.6±7.7 kgf (after 3 months of exercise training; p=0.023). Conclusion (1) The PEW group showed significantly lower %CGR than the non-PEW group. (2) An adapted low-intensity exercise program improved the muscle strength of patients with HD patients. The persistency rate of exercise training after 6 months was 50.3%, and the main reasons for dropout of exercise training were loss of motivation and leg pain.

A closer examination of three small-sample approximations to the multiple-imputation degrees of freedom, erratum

Incomplete data is a common complication in applied research. In this study, we use simulation to compare two approaches to the multiple imputation of a continuous predictor: multiple imputation through chained equations and multivariate normal imputation. This study extends earlier work by being the first to 1) compare the small-sample approximations to the multiple-imputation degrees of freedom proposed by Barnard and Rubin (1999, Biometrika 86: 948- 955); Lipsitz, Parzen, and Zhao (2002, Journal of Statistical Computation and Simulation 72: 309-318); and Reiter (2007, Biometrika 94: 502-508) and 2) ask if the sampling distribution of the t statistics is in fact a Student's t distribution with the specified degrees of freedom. In addition to varying the imputation method, we varied the number of imputa- tions (m =5 , 10, 20, 100) that were averaged over 500,000 replications to obtain the combined estimates and standard errors for a linear model that regressed the log price of a home on its age (years) and size (square feet) in a sample of 25 ob- servations. Six age values were randomly set equal to missing for each replication. As assessed by the absolute percentage and relative percentage bias, the two ap- proaches performed similarly. The absolute bias of the regression coefficients for age and size was roughly −0.1% across the levels of m for both approaches; the ab- solute bias for the constant was 0.6% for the chained-equations approach and 1.0% for the multivariate normal model. The absolute biases of the standard errors for age, size, and the constant were 0.2%, 0.3%, and 1.2%, respectively. In general, the relative percentage bias was slightly smaller for the chained-equations approach. Graphical and numerical inspection of the empirical sampling distributions for the three t statistics suggested that the area from the shoulder to the tail was reasonably well approximated by a t distribution and that the small-sample ap- proximations to the multiple-imputation degrees of freedom proposed by Barnard and Rubin and by Reiter performed satisfactorily.

THE ASSOCIATION BETWEEN MODERATE-TO-VIGOROUS PHYSICAL ACTIVITY AND MUSCLE OXIDATIVE CAPACITY IN OLDER ADULTS

Age-related decline in muscle oxidative capacity negatively affects muscle function and mobility, which may lead to disability and frailty. Whether exercise and other life-style practices reduce age-related decline in muscle oxidative capacity is unclear. We assessed whether, after accounting for age, higher daily physical activity levels are associated with greater muscle oxidative capacity. Participants included 384 adults (54.7% women) aged 22 to 92 years from the Baltimore Longitudinal Study of Aging. Muscle oxidative capacity was measured in vivo using phosphorous magnetic resonance spectroscopy. We determined the time constant for phosphocreatine recovery (τPCr, in seconds) after exercise, with lower values of τPCr reflecting greater oxidative capacity. Time spent in moderate-to-vigorous physical activity (MVPA) was assessed using accelerometers that participants wore for 5.9 ± 0.9 consecutive days in the free-living environment. In linear regression models, older age was associated with higher τPCr (β = 0.39, p-value <.001) after adjusting for sex, race, height and weight. After including MVPA as an independent variable, the standardized regression coefficient for age was attenuated by 40% to 0.22. p-value <.001). MVPA was strongly associated with lower τPCr (β = -0.33, p-value <.001) after adjusting for health status, education and smoking history and was only attenuated by 3% after additional adjustment for age. These results suggest that MVPA is strongly associated with muscle oxidative capacity independent of age, providing mechanistic insights into the health benefits of daily physical activity in older persons.

Derivation and Validation of a Scoring System to Stratify Risk for Advanced Colorectal Neoplasia in Asymptomatic Adults: A Cross-sectional Study.

Several methods are recommended equally strongly for colorectal cancer screening in average-risk persons. Risk stratification would enable tailoring of screening within this group, with less invasive tests (sigmoidoscopy or occult blood tests) for lower-risk persons and colonoscopy for higher-risk persons. To create a risk index for advanced neoplasia (colorectal cancer and adenomas or serrated polyps ≥1.0 cm, villous histology, or high-grade dysplasia) anywhere in the colorectum, using the most common risk factors for colorectal neoplasia. Cross-sectional study. Multiple endoscopy units, primarily in the Midwest. Persons aged 50 to 80 years undergoing initial screening colonoscopy (December 2004 to September 2011). Derivation and validation of a risk index based on points from regression coefficients for age, sex, waist circumference, cigarette smoking, and family history of colorectal cancer. Among 2993 persons in the derivation set, prevalence of advanced neoplasia was 9.4%. Risks for advanced neoplasia in persons at very low, low, intermediate, and high risk were 1.92% (95% CI, 0.63% to 4.43%), 4.88% (CI, 3.79% to 6.18%), 9.93% (CI, 8.09% to 12.0%), and 24.9% (CI, 21.1% to 29.1%), respectively (P < 0.001). Sigmoidoscopy to the descending colon in the low-risk groups would have detected 51 of 70 (73% [CI, 61% to 83%]) advanced neoplasms. Among 1467 persons in the validation set, corresponding risks for advanced neoplasia were 1.65% (CI, 0.20% to 5.84%), 3.31% (CI, 2.08% to 4.97%), 10.9% (CI, 8.26% to 14.1%), and 22.3% (CI, 16.9% to 28.5%), respectively (P < 0.001). Sigmoidoscopy would have detected 21 of 24 (87.5% [CI, 68% to 97%]) advanced neoplasms. Split-sample validation; results apply to first-time screening. This index stratifies risk for advanced neoplasia among average-risk persons by identifying lower-risk groups for which noncolonoscopy strategies may be effective and efficient and a higher-risk group for which colonoscopy may be preferred. National Cancer Institute, Walther Cancer Institute, Indiana University Simon Cancer Center, and Indiana Clinical and Translational Sciences Institute.

Heritability of clubfoot: A twin study

IntroductionThe aetiology of congenital clubfoot is unclear. Although studies on populations, families, and twins suggest a genetic component to the aetiology, other studies have identified environmental factors. The purpose of this study was to calculate heritability in order to determine to what extent genetic and/or environmental factors contribute to the aetiology of congenital clubfoot and to asses whether there was a change in the prevalence over time.Materials and MethodsThe Odense based Danish Twin Registry is unique as it contains data on all the approximately 85,000 twin pairs born in Denmark over the last 140 years. All 46,418 twin individuals born from 1931 through 1982, who had earlier consented to contact, received a 17-page Omnibus questionnaire in the spring of 2002. Data were analysed with structural equation models to identify the best fitting aetiological model based on a balance of goodness-of-fit and parsimony and to estimate heritability.ResultsWe found an overall self-reported prevalence of congenital clubfoot of 0.0027 (95 % confidence interval 0.0022–0.0034). Fifty-five complete (both twins answered the question) twin pairs were identified representing 12 monozygotic, 22 same-sex dizygotic, 18 opposite-sex dizygotic, and 3 with unclassified zygosity. The model with only environmental factors (CE) was best fitting based on AIC, and the model with an additive genetic factor (ACE) came in second. Due to the small statistical power, we hypothesise that the model with both genetic and environmental effects (ACE) was the better model. Choosing the ACE-model we found a heritability of clubfoot of 30 %. Regression coefficient for age was −0.002 (−0.011 to 0.005), indicating that there has been no change in prevalence of clubfoot over the 50-year age span we examined.DiscussionWe conclude that non-genetic factors must play a role, and a genetic factor might contribute, in the aetiology of congenital clubfoot.

“Linearity assessment methods for sex steroid hormones and carrier proteins among men in the National Health and Nutrition Examination Survey (NHANES III)”

IntroductionIt has been hypothesized that racial disparities among several diseases are explained by differences in testosterone (T), 17-β estradiol (E), sex hormone binding globulin (SHBG) and albumin (A) levels, yet epidemiologic results have been mixed. Statistical advice regarding appropriate adjustment methods for carrier proteins of sex steroid hormones in the literature is scant. Therefore, we investigated different adjustment methods for carrier proteins. MethodsData for 1496 men, >17years from the Third National Health and Nutrition Examination Survey (NHANES III) 1988–91 were used to analyze linearity between sex hormones and carrier proteins by examining correlation, plots, and regression models. The statistical importance of age, body mass index (BMI), and race/ethnicity were examined for changes in results by the adjustment method. ResultsT was weakly correlated with SHBG and A (r-squared, 0.25, 0.13, respectively) and E was weakly negatively correlated with A (p<0.0001), but not SHBG (p<0.1799). Based on the model residual plots and r-squared, the categorical model performed better than linear models. Regression coefficients for age, BMI, and race/ethnicity groups using quotient (e.g., T/A and E/A) models differed from continuous and categorical models. ConclusionChoosing an appropriate adjustment for carrier proteins is important to prevent bias in analyses and inconsistency in findings across studies. Linearity between variables should not be assumed when adjusting models, and should be conducted and reported. An independent categorical carrier protein variable is recommended in analysis exploring factors predicting sex hormone levels, although statistical testing should always be employed.

Abstract 9458: Coronary CT Angiography for Re-Adjustment of Pre-Test Probability of Obstructive Coronary Artery Disease

Backgrounds: Although various clinical algorithms have been proposed for defining pre-test probability of obstructive coronary artery disease (CAD), including Duke clinical score, these metrics suffer from selection bias of inclusion of predominantly high-risk population suitable for conventional coronary angiography. However, with noninvasive coronary CT angiography (CTA) comparative anatomy may also be available for a larger number of low and intermediate risk subjects, and may allow development of more inclusive algorithms. Methods: 3468 consecutive patients underwent CTA for suspected CAD (65.3±11.3 years, M:F: 1837:1811); patients with known CAD and those showing poor image quality were excluded from the study. Regression coefficients of age, gender, coronary risk factors including hypertension (HT), diabetes (DM), hyperlipidemia (HL) and smoking, history of cerebral infarction and chest symptoms (typical, atypical, or none) were weighed as predictors for CAD by multivariate analysis using logistic regression analysis against CTA findings. Risk score (K-risk) regarding the pre-test probability of CAD were calculated using each regression coefficients Results: Regression coefficients of age, gender, HT, DM, HL, smoking, history of cerebral infarction, chest symptom were 1.222, 0.039, 0.386, 0.768, 0.818, 0.385, 0.587, 0.431, respectively, and constant -6.404. The rate of concordance of K-risk and observation value was 82.8%. Area under curve of K-risk calculated by receiver operating characteristic curve was greater than that of Duke clinical score (0.769 vs 0.734 p=0.003). Conclusions: A K-risk score developed by comparison to CTA findings in the real-world population with suspected CAD allows for a superior assessment of pre-test probability of CAD. Further study for precision of it would be needed in a multicenter trial.

Genetic epidemiology of Scheuermann's disease

Background and purpose The genetic/environmental etiology of Scheuermann's disease is unclear. We estimated the heritability of the disease using an etiological model adjusted for sex and time of diagnosis, and examined whether the prevalence of Scheuermann's disease was constant over time.Methods 46,418 twins were sent a questionnaire about health and disease. Of these, 75% returned the questionnaire and 97% answered the question “Have you been diagnosed as having Scheuermann's disease by a doctor?”Results Responders included 11,436 complete pairs of twins. Data were analysed using classical twin modeling methods. Tetrachoric correlations were used to decide which etiological model to fit. The best-fitting model was the AE model. Heritability was 0.74 (95% CI: 0.65–0.81), while variance explained by environmental factors was 0.26 (95% CI: 0.19–0.35). A threshold of 2.1 (95% CI: 1.9–2.2) was calculated, corresponding to a prevalence of 1.9% (95% CI: 1.3–2.8) for women. Regression coefficients for age and sex were 0.000 (95% CI: –0.003 to 0.002) and –0.32 (95% CI: –0.42 to –0.23).Interpretation We found a heritability of 0.74 in Scheuermann's disease. The threshold in men was lower than in women, corresponding to a male prevalence that was almost twice that of females. We found no change in the prevalence of Scheuermann's disease throughout the 50-year age span that we examined.

Modeling the effect of age at calving × breed group of dam's interaction on weaning weight of Charolais-Zebu crossbred calves

The objective of this study was to evaluate alternatives for modeling the interaction between age of dam at calving (AOD) and the dam genetic group (DGG) on the weaning weight (W225) of Charolais-Zebu (Ch-Z) crossbred calves. Data from 56,965 crossbred calves were analyzed by the least square method. Regression coefficients for age of dam at calving were estimated nested into each class of the dam genetic group (CLA model); for age of dam at calving × dam Charolais percentage (age of dam at calving × FCh) and age of dam at calving × dam heterozygosity (age of dam at calving × FH) (FChFH model); for age of dam at calving × dam Charolais percentage (FCh model); for age of dam at calving × FH (FH model); or only for age of dam at calving (NINT model). Segmented polynomials were used to model the general shape of the age of dam at calving effect and its interaction with dam genetic group. The knots were at 6.33 and 10.66 years of age of dam at calving and general linear and quadratic coefficient regression and specific quadratic coefficient regression after each knot were fitted. The regression coefficients were estimated nested within sex of the calf in all situations. According to the F test for sum of squared residuals differences, the inclusion of the age of dam at calving × FH interaction did not improve the fit of the model and the CLA model provided the best fit. However, the estimates of the age of dam at calving and dam genetic group interaction from the CLA model for dam genetic group × sex of the calf classes with few records were not appropriate, but the estimates of the age of dam at calving and dam genetic group interaction from the FCh model for those classes were appropriate. The differences were small in the estimates of the age of dam of calving and dam genetic group interaction from the CLA or FCh models for dam genetic group × sex of the calf classes with many records.

Evaluation of the age-related changes in movement smoothness in the lower extremity joints during lifting

The purpose of this study was to analyze age-related movement smoothness changes in the lower extremity joints during load lifting. A total of 10 young and 13 elderly subjects participated in the study. Infrared reflective markers were attached to body landmarks in each subject. While the subjects stood on force plates and lifted a box, the marker displacements and ground reaction forces were measured using a 3D motion analysis system. The jerk square mean value (JSM) was defined as the lower extremity joint movement smoothness index during lifting. JSM represented the average of the square of the joint angle third derivative value, according to the jerk third derivative of the position data. Each subject's JSM values were calculated for the hip, knee and ankle joints. Movement smoothness appeared to decrease as JSM increased. Multiple regression analyses were performed for dependent variables (hip, knee and ankle joint JSM values) and independent variables (age, hand grip strength, sex difference and lifting duration). The level of significance was set at p < 0.05. For the hip joint JSM, the regression coefficient for age was significantly positive and that for lifting duration was significantly negative. For the knee joint JSM, the regression coefficient for lifting duration was significantly negative. For the ankle joint JSM, the regression coefficients for age and hand grip strength were significantly positive and that for lifting duration was significantly negative. These results suggest that movement smoothness in the hip and ankle joints during lifting decreases with advancing age.