A randomised controlled trial to determine the effect on response of including a lottery incentive in health surveys [ISRCTN32203485]

Background

Postal questionnaires are an economical and simple method of data collection for research purposes but are subject to non-response bias. Several studies have explored the effect of monetary and non-monetary incentives on response. Recent meta-analyses conclude that financial incentives are an effective way of increasing response rates. However, large surveys rarely have the resources to reward individual participants. Three previous papers report on the effectiveness of lottery incentives with contradictory results. This study aimed to determine the effect of including a lottery-style incentive on response rates to a postal health survey.

Methods

Randomised controlled trial. Setting: North and West Birmingham. 8,645 patients aged 18 or over randomly selected from registers of eight general practices (family physician practices). Intervention: Inclusion of a flyer and letter with a health questionnaire informing patients that returned questionnaires would be entered into a lottery-style draw for £100 of gift vouchers. Control: Health questionnaire accompanied only by standard letter of explanation. Main outcome measures: Response rate and completion rate to questionnaire.

Results

5,209 individuals responded with identical rates in both groups (62.1%). Practice, patient age, sex and Townsend score (a postcode based deprivation measure) were identified as predictive of response, with higher response related to older age, being female and living in an area with a lower Townsend score (less deprived).

Conclusion

This RCT, using a large community based sample, found that the offer of entry into a lottery style draw for £100 of High Street vouchers has no effect on response rates to a postal health questionnaire.     

Prevention of pertussis and high expectations concerning vaccines

The basic vaccine used in the prevention of pertussis is the combined vaccine including a whole cell pertussis component and tetanus and diphtheria toxoids. Although this type of vaccine has been used more than 50 years in USA and more than 40 years in Poland it is still effective what can be evidenced by the decreased number of pertussis cases since the vaccine has been implemented. There are however some evidences that the whole cell vaccine may lead to the acute encephalopathy, fever seizures, hypotonic-hyporeactive episodes, inconsolable crying or anaphylactic reactions. But still is a lack of convincing evidences that the vaccine may be a cause of persistent brain damage. It was also shown that the longer is the period after the last dose of the vaccine the lower effectiveness was observed. Improving the safety of the pertussis vaccine was the reason of introducing the acellular vaccines in the eightieth. All these products contain pertussis toxoid and some of them contain also filamentous hemagglutinin, pertactin and fimbrial agglutinogens. Some published studies have shown that the effectiveness of these vaccines is similar to the whole cells vaccines and that the incidence of some adverse events especially seizures, hypotonic-hyporeactive episodes and inconsolable crying is lower.     

Evidence that taste buds are not present on the human adult uvula

We conducted a study to investigate whether taste buds are present on the human adult uvula. Our impetus was to determine whether surgical procedures that involve removal of the uvula can affect taste perception. Five human uvulae were removed via a modified carbon dioxide laser-assisted uvulopalatoplasty in an outpatient office setting. The uvulae were serially sectioned and stained with a solution specific for membrane-bound calcium-modulated adenosine triphosphatase, a high concentration of which is found in taste receptors. Examination of the stained sections under light microscopy failed to show that any taste receptors were present in any of the uvulae. This finding suggests that the taste disturbances noted after surgical procedures involving removal of the uvula are not attributable to a loss of taste receptors.     

Can fishes resolve temporal characteristics of sounds? New insights using auditory brainstem responses

Numerous fish species produce broad-band pulsed sounds with a distinct temporal patterning which is thought to be important during intraspecific communication. In order to determine whether fishes are able to utilize temporal characteristics of acoustic signals, time resolution was determined in four species of otophysines and anabantoids by analyzing auditory brainstem responses (ABRs) to double-click stimuli with varying click periods. At click periods of 3.5 ms, two distinct ABRs were clearly detectable in all species. The minimum pulse period resolvable by the auditory system was below 1.5 ms in each species and slightly intensity-dependent. No differences were found between vocal and non-vocal species within each taxon. Comparisons of the time resolution data to the pulse periods of intraspecific sounds in the vocal species showed that the otophysine Platydoras costatus and the anabantoid Trichopsis vittata are likely to process each pulse within a series of intraspecific sounds. However, as non-vocal and vocal species have a similar minimum resolvable click period, the high temporal resolution capacities of the auditory system of fish might not represent special adaptations for intraspecific acoustic communication. Nonetheless, we suggest that temporal characteristics of naturally occurring conspecific and heterospecific sounds provide reliable information for acoustic communication.     

Sinus tympani in surgery of the middle ear and skull base

Tympanic sinus is located at the medial wall of the tympanic cavity. It's visualisation is difficult from most of approaches. Tympanic sinus is often filled with cholesteatoma in course of chronic otitis. Intraoperative assessment of tympanic sinus was performed in 29 patients with facial recess cholesteatoma, and in 20 patients with acoustic neuroma operated with translabyrinthine approach. In the group of patients with cholesteatoma four patients underwent canal wall up tympanoplasty with posterior tympanotomy, 25 underwent canal wall down tympanoplasty. Tympanic sinus was assessed during surgery with 30 degrees endoscope. In all cases depth of the sinus was measured with the use of calibrated hook. In 11 patients depth of the sinus exceeded 4 mm. In 6 among these features of bone destruction was found.     

Risk of HCV infections among children with cancer and health-care workers in children's hospitals

Summary After the outbreak of an endemy of HCV infections in the paediatric haematology and oncology wards, epidemiological analysis was performed for cancer children, health-care workers and controls. The study included a total of 639 persons, divided into four groups. The results were as follows: 1) The number of infected paediatric cancer patients was 100/237 (42.4%). 2) Of the 44 health-care workers in the haemato-oncology ward none was infected with HCV. 3) In the other parts of the hospital, five out of 258 (1.9%) permanently employed staff at risk of occupational exposure to blood and other body fluids were infected with HCV; however, the infection rate included only nurses (5/125, i.e. 4%). 4) One hundred adults consecutively tested for anti-HCV antibodies before a planned surgical procedure were not infected with HCV (control group). This study shows that complex nonspecific prophylaxis and full awareness in everyday work has helped to prevent transmission of HCV from highly contagious patients to medical personnel, particularly to nurses who have the highest occupational risk.     

Dietary fat, body weight, and cancer: contributions of studies in rodents to understanding these cancer risk factors in humans

Understanding diet and energy balance as risk factors for breast, colon, and other cancers requires information on the contribution of each factor and of interactions among factors to cancer risk. Rodent models for breast cancer provide extensive data on effects of dietary fat and calories, energy balance, body weight gain, and physical activity on tumor development. Analyses of the combined data from many studies have shown clearly that quality and quantity of dietary fat and energy balance contribute independently to increased mammary gland tumorigenesis. These findings were seen in female rats fed diets high in fat (35-40% of calories) compared to rats fed control diets, with approximately 10% of calories as fat (Fay and Freedman, 1997, Breast Cancer Res. Treat. 46, 215-223). The methods used permit comparison of experimental and epidemiological data, and they may be useful in extrapolating between species and developing public health recommendations. In addition to the contributions of lifetime-diet composition, intake, energy balance, and physical activity to cancer risk, there are questions about the timing and duration of alterations in these factors and about the "dose-response" characteristics of cancer risk to the factors. Endocrine mechanisms may be significant in mammary gland tumor risk, but experimental and epidemiological data indicate that cancers at other sites, such as colon and liver, also are influenced by the factors listed. Other diet and lifestyle factors that influence energy, or specifically fat, metabolism may also affect risk for cancers that are promoted by increased intake of fat and calories. Studies of separate and interactive effects of dietary fat, black tea, weight gain, and mammary gland tumorigenesis (Rogers, et al, 1998, Carcinogenesis 19, 1269-1273) have been analyzed. Using adjustment of carcinogenesis endpoints for body weight, tumor burden, and latency, they were found to be related to weight gain within treatment groups in 2 of 3 experiments.      

Radiocinematographic assessment of deglutition after surgical treatment for oral and maxillary neoplasms

The authors report the results of radiocinematographic examinations of 98 patients operated on for oral and maxillary neoplasms with analysis of the disturbances of various phases of deglutition in relation to the site and extent of the operation. Leakage into lower respiratory tract is discussed. Extensive operations in the mouth and on the lower and upper jaws were found to cause disturbances of both deglutition phases, and retention of contrast in postoperative tissue defects limitation of the movements of various anatomical structures were the most frequent disturbances of deglutition.