Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Binomial Distribution”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,675 records · Page 93Linked to original sources
PubMed2003

Occupant- and crash-related factors associated with the risk of whiplash injury.

PURPOSE: Given that a motor vehicle crash (MVC) had occurred, to evaluate whether occupant- and crash-related factors, such as age, gender, seating position and type of MVC are associated with the risk of whiplash injury. METHODS: A study of occupants in cars covered by motor insurance at one of the largest insurance companies in Sweden, was undertaken during a one-year period. The study population comprised all occupants in cars exposed to an MVC in which at least one occupant was injured (n = 7120). Adjusted estimates of the relative risk of whiplash injury, associated with the different factors, were calculated by means of binomial regression analysis. RESULTS: Considering different MVCs, rear-end collisions were associated with the highest relative risk of whiplash injury when compared with side impacts (1.82; 95% CI 1.68-1.96), while drivers showed the strongest association with respect to seating position when compared with passengers in the rear seat (1.78; 95% CI 1.60-1.97). Females had a somewhat higher relative risk of whiplash injury than males (1.20; 95% CI 1.16-1.25). Regarding age, the relative risk was moderately increased across the different age groups when compared with the oldest age group. No interaction was observed on the additive scale. CONCLUSIONS: Given that an MVC had occurred, subjects exposed to a rear-end collision and drivers had a substantial increased risk of whiplash injury, while age and gender were of minor importance.

Accidents, Traffic↗
PubMed2004

The impact of a decade of changing treatment on rates of severe hypoglycemia in a population-based cohort of children with type 1 diabetes.

OBJECTIVE: To determine the impact of changes to treatment on the incidence of severe hypoglycemia and its risk factors in a large population-based cohort of children with type 1 diabetes. RESEARCH DESIGN AND METHODS: The cohort consisted of 1,335 children (age at entry 9.5 +/- 4.3 years [mean +/- SD], range 0-18), yielding 6,928 patient-years of data. The mean follow-up period was 4.7 +/- 3.1 years (range 0-10.7). Prospective assessment of severe hypoglycemia (an event leading to loss of consciousness or seizure) and associated clinical factors and outcomes was made between 1992 and 2002. Patients were reviewed every 3 months. Data were analyzed using the negative binomial regression model. RESULTS: A total of 944 severe events were recorded. The incidence of severe hypoglycemia increased significantly by 29% per year for the first 5 years but appeared to plateau over the last 5 years. The overall average HbA1c significantly decreased (by 0.2% per year) over the whole follow-up period. An increased risk of severe hypoglycemia was associated with lower HbA1c, younger age, higher insulin dose, male sex, and lower parental socioeconomic status. Of insulin therapies, only pump treatment was associated with reduced rates of severe hypoglycemia. CONCLUSIONS: Severe hypoglycemia remains a major problem for children and adolescents with type 1 diabetes. Recent approaches to therapy may be allowing a degree of improved control without the expected increased risk of severe hypoglycemia but further monitoring will be important.

Adolescent↗
PubMed2004

Intimate partner violence in China: national prevalence, risk factors and associated health problems.

CONTEXT: Intimate partner violence has been studied in many developed and developing countries. China remains one of the few large societies for which the prevalence and correlates of intimate partner violence are unknown. METHODS: Data from a nationally representative sample of women and men aged 20-64 with a spouse or other steady partner provide estimates of intimate partner violence in China. Binomial and multinomial logistic regression analyses adjusted for sample design examine risk factors and negative outcomes associated with partner violence. RESULTS: Altogether, 34% of women and 18% of men had ever been hit during their current relationship; the prevalence of hitting resulting in bleeding, bruises, swelling, or severe pain and injuries was 12% for women and 5% for men. Significant risk factors for partner violence included sexual jealousy, patriarchal beliefs, low female contribution to household income, low male socioeconomic status, alcohol consumption and residence in regions other than the South and Southeast. Severe hitting was a significant risk factor for self-reported adverse general and sexual health outcomes, including sexual dysfunction, sexual dissatisfaction and unwanted sex. CONCLUSIONS: As in other societies, intimate partner violence in China is common and is correlated with adverse general and sexual health outcomes.

Adult↗
PubMed2002

Changing incidence of lobular carcinoma in situ of the breast.

Estimating the incidence of lobular carcinoma in situ (LCIS) of the breast is challenging because it lacks both clinical and mammographic signs and is usually an incidental finding in breast biopsies performed for other reasons. In general, population-based studies are believed to provide the most accurate measures, but few documenting changes in LCIS incidence rates over time have been reported. Age-adjusted age-specific LCIS incidence rates among women with no prior history of in situ or invasive breast carcinoma from 1978 to 1998 were obtained from nine population-based cancer registries that participate in the Surveillance, Epidemiology, and End Results (SEER) Program. Linear trends were evaluated using negative binomial regression. Overall, LCIS incidence rates increased fourfold (95% confidence interval, 2.9-5.6) over the study period. Specifically, they rose from 0.90/100,000 person-years in 1978-80 to 2.83/100,000 person-years in 1987-89, but then increased only modestly up to 1996-98 where the incidence rate was 3.19/100,000 person-years. However, among women 50-79 years of age, LCIS incidence rates increased continuously over the study's duration. In 1996-98, 50-59 year-olds had the highest incidence rate (11.47/100,000 person-years) and experienced the greatest absolute increase in incidence over the study period (9.48/100,000 person-years). LCIS incidence rates have steadily increased from 1978 to 1998 only among postmenopausal women. Further research is required to assess what factors are contributing to these trends.

Adult↗
PubMed2004

The effect of a major cigarette price change on smoking behavior in california: a zero-inflated negative binomial model.

The objective of this paper is to determine the price sensitivity of smokers in their consumption of cigarettes, using evidence from a major increase in California cigarette prices due to Proposition 10 and the Tobacco Settlement. The study sample consists of individual survey data from Behavioral Risk Factor Survey (BRFS) and price data from the Bureau of Labor Statistics between 1996 and 1999. A zero-inflated negative binomial (ZINB) regression model was applied for the statistical analysis. The statistical model showed that price did not have an effect on reducing the estimated prevalence of smoking. However, it indicated that among smokers the price elasticity was at the level of -0.46 and statistically significant. Since smoking prevalence is significantly lower than it was a decade ago, price increases are becoming less effective as an inducement for hard-core smokers to quit, although they may respond by decreasing consumption. For those who only smoke occasionally (many of them being young adults) price increases alone may not be an effective inducement to quit smoking. Additional underlying behavioral factors need to be identified so that more effective anti-smoking strategies can be developed.

Adolescent↗
PubMed2005

The rare epidemiologic coincidence of diverticular disease and advanced colonic neoplasia.

BACKGROUND AND AIMS: In Western industrialised countries the prevalence of neoplastic colonic lesions and diverticular disease markedly increases with age. In contrast, the coincident occurrence of both diseases seems to fall below their individual epidemiologic estimates. Because directly comparing data are rare, this retrospective study evaluates the coincidence of neoplastic lesions and diverticular disease. PATIENT AND METHODS: A total of 1,838 patients from 1986 to 2000 were admitted to the study. For 1,326 patients-56% male (n=741), 44% female (n=585), mean age 64 (+/-11.83 SD)-with a resection due to colonic cancer, the documented findings of colonoscopy, colonic contrast enema, and/or histopathology were analysed with regard to the prevalence of colonic diverticulosis. In 512 patients--51% male (n=263), 49% female (n=249), mean age 60 (+/-12.59 SD)--with a colonic resection due to diverticulitis, the synchronous or metachronous occurrence of neoplastic colonic lesions was recorded using the database of the Tumour Centre, Aachen. To compare the observed results with published epidemiology, statistical analysis included age-referred binomial tests and an age-stratified analysis (Cochran-Mantel-Haenszel test). Odds ratios (OR) were also calculated. P<0.05 was considered to indicate locally statistical significance. RESULTS: In the cancer group, we found a statistically significant reduced rate of diverticula in nearly all age categories and the age-stratified analyses (corresponding OR 0.30-0.51). Consistently, the diverticulitis group revealed a statistically significant decreased rate of advanced colonic neoplastic lesion in nearly all age categories and all age-stratified analyses (corresponding OR 0.13-0.43). CONCLUSION: Our results indicate that patients with colonic neoplastic lesions or diverticular disease probably form heterogeneous groups. Because current results from molecular biology emphasize the impact of the extracellular matrix on the genesis of diverticulosis and colonic cancer, the observed heterogeneity could be an expression of a distinct composition of the local milieu.

Adult↗
PubMed2002

Sampling variability of the Kunst-Mackenbach relative index of inequality.

STUDY OBJECTIVE: To derive methods of calculating confidence limits for the relative index of inequality, defined by Kunst and Mackenbach as a measure of the influence of socioeconomic status on an adverse health index, such as mortality rate. The methods may be used for a health outcome recorded on a continuous scale, as a Poisson count or as a binomial variable. RESULTS AND CONCLUSION: The confidence limits depend on the sampling variability of both the mean mortality rate and the slope of the regression line of mortality on the socioeconomic status scale variable. The best method for a continuous health outcome is based on Fieller's theorem but a good approximation is obtained by substituting the confidence limits for the slope of the regression line into the formula for the calculation of the index, or by using the variance of the logarithmic transform of the index. The last method is the most appropriate for the construction of significance tests comparing indices. The mortality rates may show statistically significant departure from linearity, while not suggesting that a linear relation is inappropriate, and the main decision is whether to base the confidence limits on the conventional standard error of the slope derived from the regression analysis or whether to use the standard deviation of the estimates of mortality rates.

Age Distribution↗
PubMed2006

TISA: tissue-specific alternative splicing in human and mouse genes.

Alternative splicing (AS) is a mechanism by which multiple transcripts are produced from a single gene and is thought to be an important mechanism for tissue-specific expression of transcript isoforms. Here, we report a novel graphing method for transcript reconstruction and statistical prediction of tissue-specific AS. We applied three selection steps to generate the splice graph and predict the transcript isoforms: (i) a custom scoring rule for exon/intron sets, (ii) binomial statistics for selecting valid alternative splicing with a frequency of at least 1% for the predominant form and (iii) evaluation of transcript structure. We obtained 97 286 and 66 022 valid transcripts from 26 143 human and 27 741 mouse genes, respectively. In addition, we discovered 33 481 AS events for nine types of AS patterns in human. The statistical significance of tissue specificity for each gene, transcript and AS event was assessed based on EST tissue information, followed by a multiple testing correction procedure. In human, 12 711 genes, 16 016 transcripts and 1035 AS events were predicted to be tissue-specific (false discovery rate <0.01). This information on genes, transcript structures, AS events and their tissue specificities in human and mouse are freely accessible on the TISA website (http://tisa.kribb.re.kr/AGC/).

Alternative Splicing↗
PubMed2007

Congenital missing permanent teeth in Korean unilateral cleft lip and alveolus and unilateral cleft lip and palate patients.

OBJECTIVE: To investigate the differences in the congenital missing teeth pattern in terms of tooth type (permanent maxillary lateral incisor [MLI] and maxillary second premolar [MSP]) and sidedness (cleft vs noncleft) between boys and girls in Korean unilateral cleft lip and alveolus (UCLA) and unilateral cleft lip and palate (UCLP) patients. MATERIALS AND METHODS: This study used the charts, models, radiographs, and intraoral photographs of 90 UCLA patients and 204 UCLP patients (ages 6 to 13 years). Binomial test, chi-square test, Fisher exact test, maximum likelihood analysis of variance, and the odds ratio were performed. RESULTS: According to the relationship between the congenital missing teeth pattern and the cleft type, the UCLP patients had 2.98 times more missing MLIs and 1.80 times more missing MSPs than did the UCLA patients. The MLI was congenitally missing more in boys than in girls, but the MSP showed the opposite tendency. Boys had a higher frequency of congenital missing MLIs and MSPs on the cleft side than did girls. However, on the noncleft side and both sides, girls had a higher frequency of congenital missing MLIs and MSPs than did boys. Results showed a gender-dominant pattern of congenital missing MLIs and MSPs. CONCLUSION: These results suggest that gender and cleft type might affect the congenital missing teeth pattern in terms of tooth type and sidedness.

Adolescent↗
PubMed1994

Comparing several proportions when the exposure variable is either ordinal or ratio which has been grouped into discrete classes.

The 2-by-C chi 2 test is used for comparing the proportion of "positives" of a binomial response variable among the C levels of an exposure variable. There are actually several versions of the chi 2 test that are fundamentally different, and each is meaningful only for a particular measurement scale of the exposure variable. The ordinary chi-square, which is often used indiscriminately for comparing proportions, is in fact only valid for nominal exposure variable, the chi 2 test for trend is meaningful only for ordinal exposure variable, and the regression-like chi 2 is suitable only for ratio exposure variable which has been grouped into a few discrete classes. Two SAS programs (PC SAS Release 6.04) to carry out the 2-by-C chi 2 test, one for ordinal exposure and the other for discretized-ratio exposure, were described. In addition to the chi 2 test, the programs also compute the exact probability confidence interval of the proportion for each exposure level. Numeric examples were used to illustrate the application of the programs.

Chi-Square Distribution↗
PubMed2005

Review and evaluation of methods for computing confidence intervals for the ratio of two proportions and considerations for non-inferiority clinical trials.

This article reviews several methods for forming confidence intervals for a risk ratio of two independent binomial proportions (which are both less than 0.50) and evaluates their statistical performance. These methods include use of a Taylor Series expansion to estimate variance, solutions to a quadratic equation, and maximum likelihood methods. In addition, for improvement of the properties of the methods based on large sample approximations, situations where either binomial count was less than or equal to 3 were managed conservatively by having an exact confidence interval for the odds ratio become the confidence interval for its risk ratio counterpart. Methods were initially evaluated by computing confidence limits for certain cases. Second, simulations were used to identify the better methods for controlling the Type I error rate while maintaining power. Last, relationships between methods were evaluated by calculating the percent of disagreement in the decision made regarding non inferiority. Methods in the group using a Taylor Series expansion in variance estimation perform similarly to the Pearson method preferred in the literature. In addition, the group of methods using a Taylor Series expansion are most easily computed. Applications of these findings are discussed for ratios that arise in randomized clinical trials that are conducted to show noninferiority of a new medical product to a reference control. Consideration is given as well to sample size calculations for noninferiority clinical trials.

Chi-Square Distribution↗
PubMed1996

Violence and injury in marital arguments: risk patterns and gender differences.

OBJECTIVES: Community-based research on violence against women typically focuses on marital arguments rather than on resulting injuries. This study investigated patterns of victimization, violence perpetration, and injury in marital arguments. METHODS: Data from the National Survey on Families and Households and binomial and multinomial logit models were used to analyze characteristics of those who experienced physical violence, as well as to determine who was the perpetrator and who was the victim. RESULTS: Men and women reported similar behaviors during verbal arguments. Young persons, urban dwellers, the less educated, those with low incomes, and Blacks were more likely to report that there had been physical violence in their marriages in the past year. Ethnicity, income, education, and number and age of children at home were not associated consistently with injury of the wife, the husband, or both. CONCLUSIONS: Persons who report physical violence in their marriage are very similar to those who are at increased risk of interpersonal violence in general. The co-occurrence of street and other nonfamily violence with spousal violence may be a fruitful area for future research.

Adolescent↗
PubMed2005

Prevalence of musculoskeletal activity limitation and associated factors among adults in the general population in the 1998 Quebec Health Survey.

OBJECTIVE: To estimate the prevalence of short term and longterm musculoskeletal activity limitation among the general adult population of the province of Quebec, and to identify which factors are associated with these limitations. METHODS: We analyzed cross-sectional data from the 1998 Quebec Health Survey. Logarithmic binomial regression models were used to estimate prevalence ratios of (1) short term activity limitation related to musculoskeletal disorders (MSD); and (2) longterm activity limitation related to MSD in relation to demographic and behavioral variables and comorbidity factors. RESULTS: About one-fifth of participants reporting short term activity limitation and one-third of participants reporting longterm activity limitation mentioned MSD as a cause. Multivariate analyses showed that higher age, lower income, being overweight, ill defined nervousness, and the number of traumatic events that occurred before age 18 years were significantly associated with short term and longterm activity limitation related to MSD, whereas being in the minority ethnic group was protective for both outcomes. Female sex, physical inactivity, being a former alcohol drinker, and mental disorders were also associated with longterm activity limitation. CONCLUSION: MSD are a major cause of activity limitation among adults from Quebec. With the aging population and the increasing prevalence of obesity, increasing prevalence of activity limitation related to MSD is to be expected.

Activities of Daily Living↗
PubMed2005

Occupational injury and absence from work among African American, Hispanic, and non-Hispanic White workers in the national longitudinal survey of youth.

OBJECTIVES: We examined how race and ethnicity influence injury and illness risk and number of days of work missed as a result of injury or illness. METHODS: We fit logistic regression and negative binomial regression models using generalized estimating equations with data from 1988 to 2000 on currently employed African American, Hispanic, and non-Hispanic White participants in the National Longitudinal Survey of Youth. RESULTS: Occupational factors-having a blue-collar occupation, working full-time, having longer tenure, working 1 job versus 2, and working the late shift-were associated with increased odds of an occupational injury or illness. Although racial/ethnic minority workers were no more likely than Whites to report an occupational injury or illness, they reported missing more days of work. African American and Hispanic men missed significantly more days of work than non-Hispanic White men, and African American women missed significantly more days of work than non-Hispanic White women. CONCLUSIONS: Factors associated with occupational health are multifaceted and complex. Our findings suggest that race/ethnicity influences the duration of work absence owing to injury or illness both indirectly (by influencing workers' occupational characteristics) and directly (by acting independently of occupational factors).

Absenteeism↗
PubMed2006

Anthropometric measures in relation to basal cell carcinoma: a longitudinal study.

BACKGROUND: The relationship between anthropometric indices and risk of basal cell carcinoma (BCC) is largely unknown. We aimed to examine the association between anthropometric measures and development of BCC and to demonstrate whether adherence to World Health Organisation guidelines for body mass index, waist circumference, and waist/hip ratio was associated with risk of BCC, independent of sun exposure. METHODS: Study participants were participants in a community-based skin cancer prevention trial in Nambour, a town in southeast Queensland (latitude 26 degrees S). In 1992, height, weight, and waist and hip circumferences were measured for all 1621 participants and weight was remeasured at the end of the trial in 1996. Prevalence proportion ratios were calculated using a log-binomial model to estimate the risk of BCC prior to or prevalent in 1992, while Poisson regression with robust error variances was used to estimate the relative risk of BCC during the follow-up period. RESULTS: At baseline, 94 participants had a current BCC, and 202 had a history of BCC. During the 5-year follow-up period, 179 participants developed one or more new BCCs. We found no significant association between any of the anthropometric measures or indices and risk of BCC after controlling for potential confounding factors including sun exposure. There was a suggestion that short-term weight gain may increase the risk of developing BCC for women only. CONCLUSION: Adherence to World Health Organisation guidelines for body mass index, waist circumference and waist/hip ratio is not significantly associated with occurrence of basal cell carcinomas of the skin.

Adult↗
PubMed2006

Trends in childhood injury mortality in Canada, 1979-2002.

OBJECTIVE: To examine national trends in mortality rates for injuries among Canadian children younger than 15 years in 1979-2002. METHODS: Data on injury deaths were obtained from the Canadian Vital Statistics system at Statistics Canada. Injuries were classified using the codes for external cause of injury and poisoning (E-codes) by intent and by mechanism. Mortality rates were age adjusted to the 1990 world standard population. Negative binomial regression was used to estimate the secular trends. RESULTS: Annual mortality rates for total and unintentional injuries declined substantially (from 23.8 and 21.7 in 1979 to 7.2 and 5.8 in 2002, respectively), whereas suicide deaths among children aged 10-14 showed an increasing trend. All Canadian provinces and territories showed a decreasing trend in mortality rates of total injuries. Motor vehicle related injuries were the most common cause of injury deaths (accounted for an average of 36.4% of total injury deaths), followed by suffocation (14.3%), drowning (13.5%), and burning (11.1%); however, suffocation was the leading cause for infants. The number of potential years of life lost due to injury before age 75 decreased from 89 343 in 1979 to 27 948 in 2002 for children aged 0-14 years. CONCLUSIONS: During the period 1979-2002, there were dramatic decreases in childhood mortality for total injuries and unintentional injuries as well as various degrees of reduction for all causes of injury except suffocation in children aged 10-14 years and drowning in infants. The reason for the reduction in injury mortality might be multifactoral.

Adolescent↗
PubMed2006

Ten-year health service use outcomes in a population-based cohort of 21,000 injured adults: the Manitoba injury outcome study.

OBJECTIVE: To quantify long-term health service use (HSU) following non-fatal injury in adults. METHODS: A retrospective, population-based, matched cohort study identified an inception cohort (1988-91) of injured people who had been hospitalized (ICD-9-CM 800-995) aged 18-64 years (n = 21 032) and a matched non-injured comparison group (n = 21 032) from linked administrative data from Manitoba, Canada. HSU data (on hospitalizations, cumulative length of stay, physician claims and placements in extended care services) were obtained for the 12 months before and 10 years after the injury. Negative binomial and Poisson regressions were used to quantify associations between injury and long-term HSU. FINDINGS: Statistically significant differences in the rates of HSU existed between the injured and non-injured cohorts for the pre-injury year and every year of the follow-up period. After controlling for pre-injury HSU, the attributable risk percentage indicated that 38.7% of all post-injury hospitalizations (n = 25 183), 68.9% of all years spent in hospital (n = 1031), 21.9% of physician claims (n = 269 318) and 77.1% of the care home placements (n = 189) in the injured cohort could be attributed to being injured. CONCLUSION: Many people who survive the initial period following injury, face long periods of inpatient care (and frequent readmissions), high levels of contact with physicians and an increased risk of premature placement in institutional care. Population estimates of the burden of injury could be refined by including long-term non-fatal health consequences and controlling for the effect of pre-injury comorbidity.

Adolescent↗
PubMed1999

Early age at smoking initiation and tobacco carcinogen DNA damage in the lung.

BACKGROUND: DNA adducts formed as a consequence of exposure to tobacco smoke may be involved in carcinogenesis, and their presence may indicate a high risk of lung cancer. To determine whether DNA adducts can be used as a "dosimeter" for cancer risk, we measured the adduct levels in nontumorous lung tissue and blood mononuclear cells from patients with lung cancer, and we collected data from the patients on their history of smoking. METHODS: We used the 32P-postlabeling assay to measure aromatic hydrophobic DNA adducts in nontumorous lung tissue from 143 patients and in blood mononuclear cells from 54 of these patients. From the smoking histories, we identified exposure variables associated with increased DNA adduct levels by use of multivariate analyses with negative binomial regression models. RESULTS/ CONCLUSIONS: We found statistically significant interactions for variables of current and former smoking and for other smoking variables (e.g., pack-years [number of packs smoked per day x years of smoking] or years smoked), indicating that the impact of smoking variables on DNA adduct levels may be different in current and former smokers. Consequently, our analyses indicate that models for current and former smokers should be considered separately. In current smokers, recent smoking intensity (cigarettes smoked per day) was the most important variable. In former smokers, age at smoking initiation was inversely associated with DNA adduct levels. A highly statistically significant correlation (r=.77 [Spearman's correlation]; two sided P<.001) was observed between DNA adduct levels in blood mononuclear cells and lung tissue. IMPLICATIONS: Our results in former smokers suggest that smoking during adolescence may produce physiologic changes that lead to increased DNA adduct persistence or that young smokers may be markedly susceptible to DNA adduct formation and have higher adduct burdens after they quit smoking than those who started smoking later in life.

Age Factors↗