Twin studies for the prognosis, prevention and treatment of musculoskeletal conditions

BACKGROUND

Musculoskeletal conditions are highly prevalent in our ageing society and are therefore incurring substantial increases in population levels of years lived with disability (YLD). An evidence-based approach to the prognosis, prevention, and treatment of those disorders can allow an overall improvement in the quality of life of patients, while also softening the burden on national health care systems.

METHODS

In this Masterclass article, we provide an overview of the most relevant twin study designs, their advantages, limitations and major contributions to the investigation of traits related to the domain of musculoskeletal physical therapy.

CONCLUSIONS

Twin studies can be an important scientific tool to address issues related to musculoskeletal conditions. They allow researchers to understand how genes and environment combine to influence human health and disease. Twin registries and international collaboration through existing networks can provide resources for achieving large sample sizes and access to expertise in study design and analysis of twin data.

Towards quantitative condition assessment of biodiversity outcomes: Insights from Australian marine protected areas

Protected area management effectiveness (PAME) evaluation is increasingly undertaken to evaluate governance, assess conservation outcomes and inform evidence-based management of protected areas (PAs). Within PAME, quantitative approaches to assess biodiversity outcomes are now emerging, where biological monitoring data are directly assessed against quantitative (numerically defined) condition categories (termed quantitative condition assessments). However, more commonly qualitative condition assessments are employed in PAME, which use descriptive condition categories and are evaluated largely with expert judgement that can be subject to a range of biases, such as linguistic uncertainty and overconfidence. Despite the benefits of increased transparency and repeatability of evaluations, quantitative condition assessments are rarely used in PAME. To understand why, we interviewed practitioners from all Australian marine protected area (MPA) networks, which have access to long-term biological monitoring data and are developing or conducting PAME evaluations. Our research revealed that there is a desire within management agencies to implement quantitative condition assessment of biodiversity outcomes in Australian MPAs. However, practitioners report many challenges in transitioning from undertaking qualitative to quantitative condition assessments of biodiversity outcomes, which are hampering progress. Challenges include a lack of agency capacity (staff numbers and money), knowledge gaps, and diminishing public and political support for PAs. We point to opportunities to target strategies that will assist agencies overcome these challenges, including new decision support tools, approaches to better finance conservation efforts, and to promote more management relevant science. While a single solution is unlikely to achieve full evidence-based conservation, we suggest ways for agencies to target strategies and advance PAME evaluations toward best practice.

The Impact of Receiving Predictive Genetic Information about Lynch Syndrome on Individual Colonoscopy and Smoking Behaviors

BACKGROUND

This study investigated whether receiving the results of predictive genetic testing for Lynch syndrome, indicating the presence or absence of an inherited predisposition to various cancers, including colorectal cancer, was associated with change in individual colonoscopy and smoking behaviors, which could prevent colorectal cancer.

METHODS

The study population included individuals with no previous diagnosis of colorectal cancer, whose families had already identified deleterious mutations in the mismatch repair or EPCAM genes. Hypotheses were generated from a simple health economics model and tested against individual-level panel data from the Australasian Colorectal Cancer Family Registry.

RESULTS

The empirical analysis revealed evidence consistent with some of the hypotheses, with a higher likelihood of undergoing colonoscopy in those who discovered their genetic predisposition to colorectal cancer and a lower likelihood of quitting smoking in those who discovered their lack thereof.

CONCLUSIONS

Predictive genetic information about Lynch syndrome was associated with change in individual colonoscopy and smoking behaviors but not necessarily in ways to improve population health.

IMPACT

The study findings suggest that the impact of personalized medicine on disease prevention is intricate, warranting further analyses to determine the net benefits and costs. Cancer Epidemiol Biomarkers Prev; 25(11); 1524-33. ©2016 AACR.

Quantifying the utility of single nucleotide polymorphisms to guide colorectal cancer screening

AIM

To determine whether single nucleotide polymorphisms (SNPs) can be used to identify people who should be screened for colorectal cancer.

METHODS

We simulated one million people with and without colorectal cancer based on published SNP allele frequencies and strengths of colorectal cancer association. We estimated 5-year risks of colorectal cancer by number of risk alleles.

RESULTS

We identified 45 SNPs with an average 1.14-fold increase colorectal cancer risk per allele (range: 1.05-1.53). The colorectal cancer risk for people in the highest quintile of risk alleles was 1.81-times that for the average person.

CONCLUSION

We have quantified the extent to which known susceptibility SNPs can stratify the population into clinically useful colorectal cancer risk categories.

Are we missing the boat? Current uses of long-term biological monitoring data in the evaluation and management of marine protected areas

Protected area management agencies are increasingly using management effectiveness evaluation (MEE) to better understand, learn from and improve conservation efforts around the globe. Outcome assessment is the final stage of MEE, where conservation outcomes are measured to determine whether management objectives are being achieved. When quantitative monitoring data are available, best-practice examples of outcome assessments demonstrate that data should be assessed against quantitative condition categories. Such assessments enable more transparent and repeatable integration of monitoring data into MEE, which can promote evidence-based management and improve public accountability and reporting. We interviewed key informants from marine protected area (MPA) management agencies to investigate how scientific data sources, especially long-term biological monitoring data, are currently informing conservation management. Our study revealed that even when long-term monitoring results are available, management agencies are not using them for quantitative condition assessment in MEE. Instead, many agencies conduct qualitative condition assessments, where monitoring results are interpreted using expert judgment only. Whilst we found substantial evidence for the use of long-term monitoring data in the evidence-based management of MPAs, MEE is rarely the sole mechanism that facilitates the knowledge transfer of scientific evidence to management action. This suggests that the first goal of MEE (to enable environmental accountability and reporting) is being achieved, but the second and arguably more important goal of facilitating evidence-based management is not. Given that many MEE approaches are in their infancy, recommendations are made to assist management agencies realize the full potential of long-term quantitative monitoring data for protected area evaluation and evidence-based management.

Screening participation predictors for people at familial risk of colorectal cancer: a systematic review

CONTEXT

People with a family history of colorectal cancer (CRC) are at increased risk of developing the disease. Information on the screening practices of this segment of the population is scarce.

EVIDENCE ACQUISITION

A systematic review was conducted of observational studies to identify factors associated with CRC screening participation for people at increased risk due to family history of the disease.MEDLINE, Cinahl Information Sevices, Embase, and PsycINFO databases were searched comprehensively between January 1995 and May 2012 to identify relevant articles. To be included, studies had to report on screening for people who had at least one first-degree relative with CRC, have described the study design, and reported on at least two predictors of adherence to CRC screening using a multivariate analysis.

EVIDENCE SYNTHESIS

The search identified a total of 4986 articles, of which ten met the review's inclusion criteria. There were important inconsistencies among studies in the factors that were associated with screening. Receiving recommendations from clinicians was the most consistent predictor identified across studies. The review also revealed a consistent pattern of association with predictors related to familial aspects of CRC, such as strength of family history, and relationship to the affected relative. Among the psychological constructs, "social influence" emerged as the most consistent predictor of screening participation.

CONCLUSIONS

This review provides evidence that clinicians, as well as use of family history and social networks, offer the most promising avenues to promoting and improving screening participation by individuals at increased risk of colorectal cancer.

Screening practices of Australian men and women categorized as "at or slightly above average risk" of colorectal cancer

PURPOSE

Australia has one of the highest incidences of colorectal cancer (CRC) in the world. In 2006, the federal government introduced a screening program consisting of a one-off fecal occult blood test offered to people turning 50, 55, or 65 years. We conducted a population-based study to estimate CRC screening practices existing outside the current program.

METHODS

A total of 1887 unaffected subjects categorized "at or slightly above average risk" of CRC were selected from the Australasian Colorectal Cancer Family Registry. We calculated the proportions of participants that reported appropriate, under- and over-screening according to national guidelines. We performed a logistic regression analysis to evaluate associations between over-screening and a set of socio-demographic factors.

RESULTS

Of 532 participants at average risk of CRC, eligible for screening, 4 (0.75 %) reported appropriate screening, 479 (90 %) reported never having been screened, 18 (3 %) reported some but less than appropriate screening, and 31 (6 %) reported over-screening. Of 412 participants aged 50 years or over, slightly above average risk of CRC, 1 participant (0.25 %) reported appropriate screening, 316 (77 %) reported no screening, and 11 (3 %) reported some but less than appropriate screening. Among participants under age 50 years, 2 % of those at average risk and 10 % of those slightly above average risk reported over-screening. Middle-aged people, those with a family history of CRC and those with a university degree, were more likely to be over-screened.

CONCLUSION

Overall, the level of CRC screening participation was low and the vast majority of screening tests undertaken were inappropriate in terms of timing, modality, or frequency.

Screening practices of unaffected people at familial risk of colorectal cancer

Our objective was to determine screening practices of unaffected people in the general population at moderately increased and potentially high risk of colorectal cancer (CRC) because of their family history of the disease. A total of 1,627 participants in the Australasian Colorectal Cancer Family Registry study were classified into two CRC risk categories, according to the strength of their family history of the disease. We calculated the proportion of participants that adhered to national CRC screening guidelines by age group and for each familial risk category. We carried out a multinomial logistic regression analysis to evaluate the associations between screening and sociodemographic factors. Of the 1,236 participants at moderately increased risk of CRC, 70 (6%) reported having undergone guideline-defined "appropriate" screening, 251 (20%) reported some, but less than appropriate screening, and 915 (74%) reported never having had any CRC screening test. Of the 392 participants at potentially high risk of CRC, three (1%) reported appropriate screening, 140 (36%) reported some, but less than appropriate screening, and 249 (64%) reported never having had any CRC screening test. On average, those of middle age, higher education, and who had resided in Australia longer were more likely to have had screening for CRC. The uptake of recommended screening by unaffected people at the highest familial risk of developing CRC is extremely low. Guidelines for CRC screening are not being implemented in the population. More research is needed to identify the reasons so as to enable development of strategies to improve participation in screening.

Parity and decreased use of oral contraceptives as predictors of asthma in young women

BACKGROUND

Asthma is more prevalent among males in childhood, but females report higher rates in adulthood. The reasons are unknown; although it has been hypothesized that hormonal factors may explain this sex-dependent risk of adult-onset asthma.

OBJECTIVE

To determine whether a woman's reproductive history or use of oral contraceptives is associated with adult-onset asthma.

METHODS

In 1991-1993, we surveyed 681 women aged 29-32 years randomly sampled from participants first surveyed at age 7 years by the 1968 Tasmanian Asthma Survey, a study of all children born in 1961 and attending school. Current asthma was defined as reporting asthma or wheezy breathing in the past 12 months.

RESULTS

In women who did not have asthma or wheezy breathing by age 7 years, 13% had current asthma. The risk of current asthma in these who were parous increased with the number of births (odds ratio (OR) 1.50 per birth, 95% confidence interval (CI) 1.01-2.23 P=0.04) while women with one birth were at a lower risk than nulliparous women (OR 0.46 95% CI 0.2-1.06, P=0.07). Independent of parity, the risk decreased by 7% (95% CI 0-13%) per year of oral contraceptive pill use in all women. In women who did have asthma or wheezy breathing by age 7 years, neither reproductive history nor oral contraceptive pill use predicted current asthma.

CONCLUSION

Our observation that parity and decreased oral contraceptive use predict asthma in women, is consistent with the hypothesis that the asthma that develops after childhood is in part a response to endogenous and exogenous female hormones. This may be due to alterations of cytokine responses by the pregnant state, triggering adult-onset asthma in women.

Factors in childhood as predictors of asthma in adult life

OBJECTIVE

To determine which factors measured in childhood predict asthma in adult life.

DESIGN

Prospective study over 25 years of a birth cohort initially studied at the age of 7.

SETTING

Tasmania, Australia.

SUBJECTS

1494 men and women surveyed in 1991-3 when aged 29 to 32 (75% of a random stratified sample from the 1968 Tasmanian asthma survey of children born in 1961 and at school in Tasmania).

MAIN OUTCOME MEASURES

Self reported asthma or wheezy breathing in the previous 12 months (current asthma).

RESULTS

Of the subjects with asthma or wheezy breathing by the age of 7, as reported by their parents 25.6% (190/741) reported current asthma as an adult compared with 10.8% (81/753) of subjects without parent reported childhood asthma (P < 0.001). Factors measured at the age of 7 that independently predicted current asthma as an adult were being female (odds ratio 1.57; 95% confidence interval 1.19 to 2.08); having a history of eczema (1.45; 1.04 to 2.03); having a low mild forced expiratory flow rate (interquartile odds ratio 1.40; 1.15 to 1.71); having a mother or father with a history of asthma (1.74 (1.23 to 2.47) and 1.68 (1.18 to 2.38) respectively); and having childhood asthma (1.59; 1.10 to 2.29) and, if so, having the first attack after the age of 2 (1.66; 1.17 to 2.36) or having had more than 10 attacks (1.70; 1.17 to 2.48).

CONCLUSION

Children with asthma reported by their parents in 1968 were more likely than not to be free of symptoms as adults. The subjects who had more severe asthma (especially if it developed after the age of 2 and was associated with reduced expiratory flow), were female, or had parents who had asthma were at an increased risk of having asthma as an adult. These findings have implications for the treatment and prognosis of childhood asthma, targeting preventive and educational strategies and understanding the onset of asthma in adult life.

The associations between childhood asthma and atopy, and parental asthma, hay fever and smoking

The aim of this analysis was to examine the degree to which a life time prevalence of asthma in a 7-year-old child is statistically associated with atopic conditions of the child, and with parental asthma, hay fever and smoking. In 1968, 8585 children who were born in 1961 and who were attending school in Tasmania were surveyed. This comprised 99% of the eligible population. The prevalence of a history of asthma in the 7-year-olds was 16.2% (males 19.0%, females 13.2%). Multiple logistic regression analysis showed that a history of asthma in a 7-year-old was associated with the child being male (odds ratio [OR] 1.56; 99% confidence interval 1.30-1.86), having a history of hay fever (3.86; 3.12-4.78), eczema (2.04; 1.63-2.55), hives (1.34; 1.09-1.65) or allergy to foods or medicines (1.70; 1.26-2.30), the child's mother or father having a history of asthma (2.63; 2.08-3.31 or 2.52; 1.99-3.19, respectively), and the mother being a smoker (1.26; 1.05-1.51). Parental hay fever and paternal smoking were not independently associated with childhood asthma. The strength of association between childhood asthma and parental asthma was independent of the sex of either the parent or the child, and of atopic conditions in the child. In the 133 children for whom both parents were asthmatic, 65 (49%) had a history of asthma.(ABSTRACT TRUNCATED AT 250 WORDS)

Incorporation of twins in the regressive logistic model for pedigree disease data

Segregation and twin disease concordance analyses have assumed a theoretical underlying liability following a multivariate normal distribution. For reasons of computation, of incorporation of measured explanatory variables, and of testing of fit and assumptions, newer analytical methods are being developed. The regressive logistic model (RLM) relies on expressing the pedigree likelihood as a product of conditional probabilities, one for each individual. In addition to logistic regression modelling of measured epidemiological variables on disease prevalence, there is modelling of vertical transmission, of transmission of unmeasured genotypes and of sibship environment. This paper discusses methods for the analysis of binary traits in twins and in pedigrees. Some extensions to the RLM for pedigrees which include twins are proposed. These enable exploration of twin concordance in the context of the twins' common parenthood, the sibship similarities within the family, and the twins' similarity in age, sex, genes and environment.

Mutagenic mucus in the cervix of smokers

A pilot study was conducted to determine whether any relationship exists between mutagenicity of a women's uterine cervical mucus and her current smoking status. Cervical fluids obtained from 78 premenopausal women seen between July 1983 and March 1984 at the University of California, San Francisco Dysplasia (and diethylstilbestrol) Clinic or in a private practice were tested for mutagenicity by means of the Ames-Salmonella microsomal test. Of 36 current smokers, 14 (39%) had positive tests as compared to 5 of 42 nonsmokers (12%). The odds ratio (OR) estimate was 4.7 with 95% confidence limits (CL) of 1.6-14.2. Secretions from 14 of 32 (44%) women who had smoked during the day of the sample collection--within the previous 7 hours--were positive on the laboratory test, whereas none of the 4 women was positive who had smoked 8 hours or more before the specimens were obtained. Fluids from women with dysplasia or carcinoma in situ were more likely to be mutagenic than were those from other women, although this finding may be due to chance (OR = 2.0 with 95% CL of .70-5.9). This relationship between smoking and mutagenic cervical fluids offers evidence that might help to explain the association between cervical cancer and cigarette smoking noted in previous epidemiologic studies.

Mouth breathing, occlusion, and modernization in a north Indian population. An epidemiologic study

Village-dwelling Punjabi youths show significantly better dental occlusion and less chronic respiratory allergy than their city-dwelling counterparts. Field diagnosis finds posterior crossbite the only occlusal condition correlated with mouth breathing in the samples studied.

Univariate and multivariate methods for sexing the sacrum

Metric data on 200 sacra of known sex, age and race are analyzed to determine the usefulness of conventional observations for determining sex in this bone. Results of the univariate analysis show that significant sex differences in the sacrum involve primarily the top portion of the bone for both whites and blacks. However, measurements of curvature are important sex differences in the sample of blacks. A new index relating the S1 body to sacral breadth is proposed as more useful in classifying the bones by sex than indices involving other measurements. Discriminant analysis shows that the sample of whites can be analyzed significantly better by this method than by using an index. The choice of univariate or multivariate method must depend on the condition of the bone, and will be influenced to some extent by the race from which the sample is drawn.