Non-response bias in estimates of prevalence of club-based sport participation from an Australian national physical activity, recreation and sport survey.

BACKGROUND: An estimate of the prevalence of an activity derived from a sample survey is potentially subject to non-response bias, whereby people not involved in the activity are less likely to respond than those involved. Quantifying the extent of non-response bias is generally difficult, since it involves estimating differences between respondents for whom data is directly available from the survey, and non-respondents, for whom data is generally not directly or readily available. However, in the case of the Australian Exercise Recreation and Sport Survey (ERASS), comparative "gold standard" benchmarks exist for some aspects of the survey, in the form of state sporting association (SSA) registration databases, each of which purports to constitute a complete enumeration of club-based players of a particular sport. METHODS: ERASS estimates of the prevalence of participation in four major club-based team sports in the Australian state of Victoria in the year 2010 were compared with prevalences based on numbers of registered participants in the corresponding SSA databases. Comparisons were made for the adult population as a whole (ERASS scope being 15+ years of age), and for strata defined by age and geographical region. Because three of the four sports investigated are strongly sex-specific, no sex breakdowns were conducted. In each case the proportion of ERASS respondents reporting participation, with associated confidence limits, was compared with the corresponding SSA count expressed as a proportion of the population, to form an ERASS/SSA prevalence ratio with associated confidence limits. RESULTS: The 24 ERASS/SSA ratios ranged from 1.72 to 7.80. Most ratios lay in the range 2 to 3. The lower 95% confidence bound for the ratio was greater than 1.0 in 23 out of 24 cases. CONCLUSIONS: ERASS estimates of prevalence of these particular aspects of sport participation were higher than SSA estimates, to statistically significant degrees. The effect sizes (i.e. the discrepancies represented by the ratios) were large enough to be of great practical importance. It is conjectured that non-response bias is the most likely explanation for the discrepancies.

The influence of a Healthy Welcoming Environment on participation in club sport by adolescent girls: a longitudinal study.

BACKGROUND: This study investigated the perceived influence of a Healthy Welcoming Environment (HWE) on participation in sports clubs among adolescent girls, and how these perceptions changed longitudinally. HWE was defined in terms of a set of health promotion policies advocated by a health promotion foundation as the basis of sport club health promotion practice to promote structural reform in state sporting organisations and their affiliated associations and clubs. These included sports injury prevention, smoke-free, responsible serving of alcohol, sun protection, healthy eating, and welcoming and inclusive environments. METHODS: Year 7 and 11 female students from metropolitan (n = 17) and non-metropolitan secondary schools (n = 14) in Australia were invited to participate in three annual surveys. These surveys collected information about current or past membership of a sports club and the influence of HWEs on their decision to participate (or not) in a sports club. RESULTS: Year 7 (n = 328; 74.5%) and Year 11 (n = 112; 25.5%) female students completed all three waves (19.6% response rate; 82.7 and 74.0% retention rate). Most agreed that characteristics of HWEs were a positive influence on their participation in sports clubs, except those relating to alcohol and Sunsmart. Welcoming factors had consistent high agreement among respondents. Alcohol and friendliness factors of the club were regarded as being positively influential by higher percentages of non-metropolitan than metropolitan respondents. CONCLUSIONS: Welcoming factors were the most positive influences on decisions to participate in sports clubs. These factors may be important in reducing barriers to sport participation. Strategies supporting the social environment within sports clubs should be prioritised.

Denaturing high performance liquid chromatography: high throughput mutation screening in familial hypertrophic cardiomyopathy and SNP genotyping in motor neurone disease.

AIMS: To evaluate the usefulness of denaturing high performance liquid chromatography (DHPLC) as a high throughput tool in: (1) DNA mutation detection in familial hypertrophic cardiomyopathy (FHC), and (2) single nucleotide polymorphism (SNP) discovery and validation in sporadic motor neurone disease (MND). METHODS: The coding sequence and intron-exon boundaries of the cardiac beta myosin heavy chain gene (MYH7) were screened by DHPLC for mutation identification in 150 unrelated patients diagnosed with FHC. One hundred and forty patients with sporadic MND were genotyped for the A67T SNP in the poliovirus receptor gene. All DHPLC positive signals were confirmed by conventional methods. RESULTS: Mutation screening of MYH7 covered 10 kb with a total of 5700 amplicons, and more than 6750 DHPLC injections were completed within 35 days. The causative mutation was identified in 14% of FHC cases, including seven novel missense mutations (L227V, E328G, K351E, V411I, M435T, E894G, and E927K). Genotyping of the A67T SNP was performed at two different temperatures both in MND cases and 280 controls. This coding SNP was found more frequently in MND cases (13.6%) than in controls (6.8%). Furthermore, 19 and two SNPs were identified in MYH7 and the poliovirus receptor gene, respectively, during DHPLC screening. CONCLUSIONS: DHPLC is a high throughput, sensitive, specific, and robust platform for the detection of DNA variants, such as disease causing mutations or SNPs. It enables rapid and accurate screening of large genomic regions.