Reliability and Validity of the Dutch Physical Activity Questionnaires for Children (PAQ-C) and Adolescents (PAQ-A).

BACKGROUND: This study was designed to validate the Dutch Physical Activity Questionnaires for Children (PAQ-C) and Adolescents (PAQ-A). METHODS: After adjustment of the original Canadian PAQ-C and PAQ-A (i.e. translation/back-translation and evaluation by expert committee), content validity of both PAQs was assessed and calculated using item-level (I-CVI) and scale-level (S-CVI) content validity indexes. Inter-item and inter-rater reliability of 196 PAQ-C and 95 PAQ-A filled in by both children or adolescents and their parent, were evaluated. Inter-item reliability was calculated by Cronbach's alpha (α) and inter-rater reliability was examined by percent observed agreement and weighted kappa (κ). Concurrent validity of PAQ-A was examined in a subsample of 28 obese and 16 normal-weight children by comparing it with concurrently measured physical activity using a maximal cardiopulmonary exercise test for the assessment of peak oxygen uptake (VO2 peak). RESULTS: For both PAQs, I-CVI ranged 0.67-1.00. S-CVI was 0.89 for PAQ-C and 0.90 for PAQ-A. A total of 192 PAQ-C and 94 PAQ-A were fully completed by both child and parent. Cronbach's α was 0.777 for PAQ-C and 0.758 for PAQ-A. Percent agreement ranged 59.9-74.0% for PAQ-C and 51.1-77.7% for PAQ-A, and weighted κ ranged 0.48-0.69 for PAQ-C and 0.51-0.68 for PAQ-A. The correlation between total PAQ-A score and VO2 peak - corrected for age, gender, height and weight - was 0.516 (p = 0.001). CONCLUSIONS: Both PAQs have an excellent content validity, an acceptable inter-item reliability and a moderate to good strength of inter-rater agreement. In addition, total PAQ-A score showed a moderate positive correlation with VO2 peak. Both PAQs have an acceptable to good reliability and validity, however, further validity testing is recommended to provide a more complete assessment of both PAQs.

Flemish adolescents' perceptions of cigarette plain packaging: a qualitative study with focus group discussions.

OBJECTIVES: To find out whether there is a potential impact of the appearance of a plain cigarette package on the smoking perceptions and behavioural intentions of Flemish adolescents. DESIGN: We performed a cross-sectional study using the qualitative method of focus group discussions. SETTING: Flemish adolescents. PARTICIPANTS: We performed eight focus group discussions, in which 55 adolescents took part, 32 female and 23 male. Inclusion criteria were: Flemish male and female 15-year-olds to 16-year-olds and 17-year-olds to 18-year-olds attending regular high-school education or vocational training who were current or had ever been smokers. OUTCOME MEASURE (PLANNED AS WELL AS MEASURED): The opinions and perceptions of young Flemish smokers regarding the impact of cigarette packaging on their smoking behaviour. RESULTS: Plain packages are perceived as less attractive, cheap and unreliable for young people. Because of the unattractiveness of the plain packaging, the health warnings catch the eye much more strongly. CONCLUSIONS: In this first scientific study in Flanders on this topic, it emerged that plain packaging could be a strong policy tool to reduce the number of adolescents starting smoking. Validation of these findings by conducting a quantitative survey in the same target group is recommended.

Population-based screening for colorectal cancer using an immunochemical faecal occult blood test: a comparison of two invitation strategies.

BACKGROUND: To date, there is no screening programme for colorectal cancer (CRC) in Flanders, Belgium. However, The European Code Against Cancer (2003) recommends a population-based approach for CRC screening. This study aimed to obtain information about potential participation rates for a population-based screening programme for CRC in Flanders, and to compare two invitation strategies. METHODS: In 2009, a trial programme for CRC screening was set up in three Flemish areas for all average-risk people aged 50-74 years, using an immunochemical faecal occult blood test (iFOBT) with a cut-off value set at 75 ng/ml of haemoglobin. The faecal sampling set was sent at random by post (mail group) or provided by the general practitioner (GP group). RESULTS: In total, 19,542 people were invited to participate. Of these, 8229 provided a faecal sample, resulting in an overall participation rate of 42.1%. Participation by mail and through the GP was 52.3% (95% CI, 51.3-53.2) and 27.7% (95% CI, 26.7-28.6), respectively. The difference of 24.6% was statistically significant (95% CI, 23.3-25.9, p<0.001). Before the reminder letter was sent and the other invitation strategy was offered, the overall participation rate was 26.5% (n=5176); 36.4% (95% CI, 35.5-37.4) for the mail group and 16.6% (95% CI, 15.8-17.3) for the GP group. The odds of participating in CRC screening was almost three times higher for people invited by mail as opposed to people invited through a GP (OR=2.96, 95% CI, 2.78-3.14, p<0.001). Women were more likely to participate in CRC screening than men (OR=1.22, 95% CI, 1.15-1.30, p<0.001). In addition, we found that inhabitants from residential (OR=1.98, 95% CI, 1.85-2.11) and rural (OR=2.90, 95% CI, 2.66-3.16) areas were more likely to participate than those in urban areas. Of the 8229 people who submitted a faecal sample, 435 (5.3%) had a positive iFOBT, and of those, CRC was diagnosed in 18 (5.7%) individuals. Compliance for follow-up colonoscopy was 72.9%, and did not differ between the mail (72.4%, 95% CI, 67.5-77.3) and GP groups (74.3, 95% CI, 66.2-82.5). CONCLUSION: Inviting people for CRC screening by means of a direct-mail invitation, and including a faecal sampling set (iFOBT), results in much higher participation rates than inviting people through the GP.

Screening for colorectal cancer: sense and sensibilities.

PURPOSE: In this paper we investigate the reasons for non-participation in a trial programme for colorectal cancer (CRC) screening in Flanders. Besides, the feasibility and possibilities of a full-blown screening programme in Flanders are examined, given the context of a low participation rate in breast cancer screening. METHODS: A trial programme for CRC screening was set up for all average-risk persons aged 50 to 74 years in three Flemish regions to obtain information about potential participation rates, and to compare two invitation strategies. Faecal samples were analysed for precursors of CRC using an immunochemical faecal occult blood test (iFOBT). A questionnaire was administered to participants and non-participants of the trial programme to find out whether and to what extent the taking of a sample of one's own stool is a taboo. This could be of great importance concerning the participation rate. RESULTS: In total, 19,542 persons were invited to participate in the trial programme for CRC screening, of whom 18,541 were found to be eligible. The overall participation rate was 44.3%. The three regions varied in participation rates: with 60.9% in the most rural region to 34.3% in the most urban region. Of 2,000 questionnaires sent to participants, 1,385 were returned (69.3%). The response in the non-participants was 43.2%i (691 questionnaires of 1,600 returned). CONCLUSIONS: A population-based screening programme for colorectal cancer by means of an iFOBT proves to be feasible, since adequate participation rates were obtained and because of the absence of a 'stool taboo' in Flanders.

Medical students trained in communication skills show a decline in patient-centred attitudes: an observational study comparing two cohorts during clinical clerkships.

OBJECTIVE: Literature indicates a decline in patient-centredness in medical students, especially during clinical clerkships. We examined the impact of preclinical communication skills training (CST) on students' development of patient-centred attitudes and attitudes toward CST during clerkships. METHODS: We prospectively compared two cohorts before and after clerkships: one cohort (n=48) had not received CST, whereas the other (n=37) had received a five-year CST. We assessed the impact using five validated questionnaires. RESULTS: Communication trained students slightly but significantly declined in patient-centred attitudes (3/4 scales) and attitudes toward CST during clerkships, whereas the scores of the untrained students remained stable (5/5 scales). Both cohorts did not differ in attitudes before clerkships. In the trained cohort, males mostly showed a sharper decline than females. In the total group (n=85), females demonstrated higher attitude scores toward CST, and in 1/4 scales measuring patient-centred attitudes. CONCLUSION: This cohort study suggests that CST might make students more vulnerable to decline in attitude scores during clerkships. PRACTICE IMPLICATIONS: These remarkable findings, contrary to what educators would expect to result from their efforts, challenge medical education to address the new questions that are raised about the validity of the questionnaires, the impact of CST and the learning processes involved in the development of patient-centredness.

Air pollution and exhaled nitric oxide in Dutch schoolchildren.

BACKGROUND: Short-term changes in air pollution exposure in children may be associated with transient increases in exhaled nitric oxide (NO), a marker of airway inflammation. Also, children living in areas with high air pollution levels and/or high traffic densities appear to have chronically increased levels of exhaled NO. No studies have simultaneously addressed the long-term and short-term associations between traffic-related air pollution and exhaled NO. OBJECTIVES: To investigate associations between exhaled NO in school children and both short-term changes in outdoor PM(10) and long-term traffic exposures. METHODS: Offline exhaled NO measurements were conducted in 812 children from nine Dutch schools within 400 m of motorways. Daily levels of particulate matter with a 50% cut-off aerodynamic diameter of 10 µm (PM(10)) were obtained from background monitoring stations. Long-term exposure to traffic-related air pollution was assessed using specific traffic-related characteristics such as total, car and truck motorway traffic and the distances of the children's homes and schools from the motorway. RESULTS: A positive association was found between ambient PM(10) concentrations on the day of exhaled NO measurement and exhaled NO (adjusted geometric means ratio (95% CI) 2.24 (1.37 to 3.65)) over the range of daily PM(10) concentrations of 44 µg/m(3)), which was largely attributable to a pollution peak associated with high particulate matter emissions from traditional Easter fires. There were suggestive associations between exhaled NO and traffic counts only in children with asthma, which were not statistically significance. CONCLUSIONS: Short-term changes in ambient PM(10) largely attributable to biomass burning are associated with increased levels of exhaled NO.

Traffic-related outdoor air pollution and respiratory symptoms in children: the impact of adjustment for exposure measurement error.

BACKGROUND: Outdoor concentrations of soot and nitrogen dioxide (NO2) outside of schools have been associated with children's respiratory and eye symptoms. We assessed how adjustments for measurement error affect these associations. METHODS: Concentrations of air pollutants outside children's schools were validated by personal measurements of exposure to traffic-related air pollution. We estimated prevalence ratios of 4 health outcomes (current wheeze, conjunctivitis, phlegm, and elevated total serum immunoglobulin E) using school outdoor measurements, and then adjusted for measurement error using the personal exposure data and applying a regression calibration method. The analysis adjusting for measurement error was carried out using a main study/external validation design. RESULTS: Adjusting for measurement error produced effect estimates related to soot and NO2 that were 2 to 3 times higher than in the original study. The adjusted prevalence ratio for current phlegm was 5.3 (95% confidence interval = 1.2-23) for a 9.3 microg/m3 increase in soot, and 3.8 (1.0-14), for a 17.6 microg/m3 increase in NO2, compared with the original results of 2.2 (1.3-3.9) and 1.8 (1.1-2.8), respectively. Corrections were of similar magnitude for the prevalence of current wheeze, current conjunctivitis, and total elevated total immunoglobulin E. CONCLUSIONS: The estimated effects of outdoor air pollution on respiratory and other health effects in children may be substantially attenuated when based on exposure measurements outside schools instead of personal exposure.

Validity of residential traffic intensity as an estimate of long-term personal exposure to traffic-related air pollution among adults.

The validity of traffic intensity near the home as an estimate for the personal long-term exposure to traffic-related air pollution in an adult population was tested. Personal and near-home outdoor exposure to PM2.5, soot, NO, NO2, and NOx was monitored four to five times during 48 h periods in older adults. A group of 23 participants lived in high traffic intensity streets (>10000 vehicles/(24 h)), and 22 lived in low traffic intensity streets. The relation between average personal exposure and traffic intensity at the residential address was explored by taking indoor sources into account. Large differences in the measured outdoor concentrations between locations in high traffic and low traffic intensity streets were found for soot (68%), NO (127%), and NOx (35%). Differences were smaller for PM2.5 (14%) and NO2 (22%). Slightly elevated ratios were found for personal exposure to soot (1.15; 95% confidence interval (CI), 1.01-1.30)when comparing adults living in high traffic intensity streets with adults living in low traffic intensity streets. For NO, increased personal exposure (1.16) was seen for the same comparison, but this difference failed to reach statistical significance (CI, 0.80-1.66). Traffic intensity on the street of residence predicted personal exposure to soot but not to PM2.5 or nitrogen oxides. Traffic intensity may not correlate well to personal exposure and accordingly substantial misclassification of exposure may occur when traffic intensity is used as an exposure indicator in epidemiological studies. Time spent in traffic and spending time outdoors were associated with increased personal exposure of soot and PM2.5, but not NOx.

Long-term personal exposure to traffic-related air pollution among school children, a validation study.

Several recent studies suggest an association between long-term exposure to traffic-related air pollution and health. Most studies use indicators of exposure such as outdoor air pollution or traffic density on the street of residence. Little information is available about the validity of these measurements as an estimate of long-term personal exposure to traffic-related air pollution. In this pilot study, we assessed outdoor and personal exposure to traffic-related air pollution in children living in homes on streets with different degree of traffic intensity. The personal exposure of 14 children aged 9-12 years to 'soot', NO(x) (NO and NO(2)) was assessed in Amsterdam between March and June 2003. Each child's personal exposure was monitored during four repeated 48-h periods. Concurrently, in- and outdoor NO(x) measurements were carried out at the school and at the home of each participating child. Measurements were supplemented by a questionnaire on time activity patterns and possible indoor sources. Flow-controlled battery operated pumps in a made-to-fit backpack were used to sample personal exposure to 'soot', determined from the reflectance of PM(2.5) filters. Exposure to NO(x) was assessed using Ogawa passive samplers. Children living near busy roads were found to have a 35% higher personal exposure to 'soot' than children living at an urban background location, despite that all children attended the same school that was located away from busy roads. Smaller contrasts in personal exposure were found for NO (14%), NO(2) (15%) and NO(x) (14%). This finding supports the use of 'living near a busy road' as a measure of exposure in epidemiological studies on the effects of traffic-related air pollution in children.

The reliability of ten-year dietary recall: implications for cancer research.

Remote dietary intakes may be more important than recent diet in the etiology of cancer because of the long latency in cancer development. We examined the reliability of remote dietary recall over 10 y. Subjects were 56 adults participating in a cancer prevention trial in Western Australia. All subjects completed a 28-d diet record (DR) in 1991. A food-frequency questionnaire (FFQ) modified to ask respondents about their diet 10 y earlier was sent to each subject for completion in 2001. Remote intakes recalled from 10 y earlier using the FFQ were compared with the DR using the limits of agreement (LOA) method and Pearson correlation coefficients. Mean intakes of most nutrients did not differ between dietary methods. The LOA indicated that the FFQ could under- or overestimate DR estimates by >/=50%. For many nutrients, agreement between methods depended on the magnitude of intake. Pearson's correlation coefficients ranged from 0.02 for retinol to 0.66 for alcohol. These findings are similar to those of other studies that examined the reliability of recent and remote dietary intakes. They also show that using this FFQ, remote diet recalled from 10 y earlier may be as reliable as recent dietary recall.