Receptor Activator of Nuclear Factor kappa-B Ligand is Not Regulated During Chronic Osteomyelitis in Pigs.

Bone loss is a major complication of osteomyelitis and from numerous in-vitro studies, it has been concluded that the bone lysis is caused by elevated expression of the receptor activator of nuclear factor κB ligand (RANKL), leading to increased osteoclast activity. However, we failed to find any relationship between bone loss and osseous RANKL expression in a porcine model of acute and chronic implant-associated osteomyelitis (IAO) due to Staphylococcus aureus or in chronic osteomyelitis lesions in slaughter pigs. Surprisingly, we found that the expression of RANKL was reduced during chronic bone infections. This is in line with the few studies conducted on human samples. A significant bone loss was observed in IAO lesions and in lesions from slaughter pigs, but with no indication of osteoclast involvement using histochemistry, immunohistochemistry for RANKL, receptor activator of nuclear factor kappa-B, osteoprotegerin and cathepsin K, and high-throughput quantitative real-time polymerase chain reaction on bone tissue from osteomyelitic lesions. A strong inflammatory response was seen in the infected animals and, therefore, we propose proteolytic enzymes induced by inflammation to be a major component of the bone loss. Furthermore, we found a significant upregulation of the IL26 gene in infected animals, which can inhibit RANKL-induced osteoclastogenesis, but has no homologue in mice. This finding emphasises that neither murine models nor in-vitro studies can mirror human disease development completely. The present study emphasises that the interactions between microorganisms, the immune system and bone cells in osteomyelitis are too complex to be accurately represented by an in-vitro model.

Guideline for Preclinical Studies of Bone Infections in Large Animals Based on a Systematic Review of 316 Non-Rodent Models.

BACKGROUND: In recent years, animal models of bone infections have been used with increased frequency in order to evaluate novel diagnostic and anti-infective technologies, like antibacterial coating of bone implants or local antibiotic carrier products. Therefore, it is highly relevant to evaluate the scientific quality of existing bone infection models. METHODS: We conducted a systematic review of 316 studies of large non-rodent animal models of bone infection (254 rabbit, 16 pig, 23 dog, 11 goat, and 12 sheep) and extracted data on study design, methodological quality, and postmortem evaluation of infection with respect to reporting and quantification of pathology and microbiology. RESULTS: The review demonstrated a substantial lack of study-design information, which hampers reproducibility and continuation of the established work. Furthermore, the methodological study quality was found to be low, as the definition of infection, randomization, power analysis, and blinding were only seldomly reported. The use of histology increased in recent years, but a semi-quantitative scoring of the lesions was often missing, i.e. no objective quantification of outcome. Most of the studies focused on whether the inoculated bacteria were present within the bone tissue post mortem or not. However, very often the bacterial burden was not quantified. In many of the models, different antimicrobial interventions were examined and, although antimicrobial effects were commonly described, a lack of complete sterile outcome was observed in many models. On the basis of the systematic review, we established a study template providing a guideline for the standard reporting of animal models of bone infections, including details related to the animal, pathogen, infected animal, and postmortem analysis that are of crucial importance for validation of results and reproducibility. CONCLUSIONS: As the aim of many bone infection models is to examine the effect of an intervention, the guideline emphasizes the importance of objective quantification of outcome, e.g., blinded quantitative scoring of histological findings and quantification of bacterial burden within tissue and on inserted implants. Less than 5% of the analyzed studies adhered completely to the ideal form presented in the study template. CLINICAL RELEVANCE: Anti-infective interventions must be tested in preclinical animal models before implementation in human patients, and optimal design and validation is essential for a high translational value.

Geochemistry of a copper mine tailings deposit in Repparfjorden, northern Norway.

This study investigates copper ore tailings deposited in Repparfjorden, Norway in the 1970's. Bathymetric show that the tailings deposit still occurs as a series of cone-shapes and has retained its original shape for four decades. Analytical data of 51 chemical elements show that some of the tailings are spreading, affecting fjord surface sediments in the inner part of the fjord. The deposited tailings are clearly enriched on the elements Ba, Bi, Cu, Hf and Zr and depleted of Ca, Li, Nb, Pb, Sc, V and Y. A hard pan horizon occurs at 20 cm sediment depth in large parts of the inner inlet, which seems to have precipitated during the deposition of tailings. New tailings were fabricated from the two local mineralisations and these display varying chemical results from each other but also in respect to the old, deposited tailings. Therefore, caution should be taken when making chemical predictions for a future deposit.

A qualitative study of the key factors in implementing telemedical monitoring of diabetic foot ulcer patients.

INTRODUCTION: The implementation of telemedicine often introduces major organizational changes in the affected healthcare sector. The objective of this study was to examine the organizational changes through the perception of the healthcare professionals regarding the implementation of a telemedical intervention. We posed the following research question: What are the key organizational factors in the implementation of telemedicine in wound care? METHODS: In connection with a randomized controlled trial of telemedical intervention for patients with diabetic foot ulcers in the region of Southern Denmark, we conducted an organizational analysis. The trial was designed as a multidisciplinary assessment of outcomes using the Model of ASsessment of Telemedicine (MAST). We conducted eight semi-structured interviews including individual interviews with leaders, and an IT specialist as well as focus group interviews with the clinical staff. A qualitative data analysis of the interviews was performed in order to analyze the healthcare professionals and leaders perception of the organizational changes caused by the implementation of the intervention. RESULTS: The telemedical setup enhanced confidence among collaborators and improved the wound care skills of the visiting nurses from the municipality. The effect was related to the direct communication between visiting nurses and specialist doctors. Focus on the training of the visiting nurses was highlighted as a key factor in the success to securing implementation. Concerns regarding lack of multidisciplinary wound care teams, patient responsibility and lack of patient interaction with the physician were raised. Furthermore, the need for clinical guidelines in future implementation was underlined. CONCLUSIONS: Several influential factors were demonstrated in the analysis including visiting nurses wound care training, focus on management, economy, periods with absence from work and clinical care. However, the technology used here could provide an additional option to offer patients after an individual assessment of their health condition.

Phthalates and food-contact materials: enforcing the 2008 European Union plastics legislation.

The migration of phthalates into foodstuffs from food-contact materials (FCM) is a well-known source of food contamination. In 2005, the European Food Safety Authority finalized its risk assessment for several of the classical phthalate plasticizers. In their risk management procedure the European Commission transformed the tolerable daily intakes established by the Authority into legislative limits for phthalates in both plastic and food simulants, while taking exposure from other sources into consideration. These limits have been into force since 1 July 2008. A detailed interpretation of the regulation of these substances was agreed upon in the European network of FCM reference laboratories. This paper reports results from a Danish control campaign of samples collected by official food inspectors and analysed by a newly validated analytical method run under accreditation. Samples were from FCM producers, FCM importers and importers of packed foodstuffs from third-party countries. Products containing phthalates above the current limits were found in several categories of FCM: conveyor belts (six of six), lids from packed foodstuffs in glasses (eight of 28), tubes for liquid foodstuffs (four of five) and gloves (five of 14). More than 20% of the samples analysed contained dibutylphthalate (DBP) or di-(2-ethylhexyl)phthalate (DEHP) above the compositional limits of 0.05% and 0.1%, respectively. Analysis of residual phthalates in metal lid gaskets instead of analysis of phthalates in the food when controlling foodstuffs packed outside the European Union proved to be an efficient and simple control method. All findings of phthalates were associated with the use of plasticized polyvinylchloride (PVC).

Exposure assessment of kneeling work activities among floor layers.

The objective of this study was to quantify the proportion of kneeling work activities among floor layers and to assess external knee joint forces in five different kneeling work positions. Thirty-three floor layers were videotaped discontinuously and four floor layers were videotaped continuously for a whole working day. External knee forces were measured in five different kneeling work positions in ten floor layers using Computer Dynography. The study showed that floor layers spent a high percentage of time in knee-straining work positions. Kneeling work tasks, particularly gluing and crawling caused high external knee forces ranging from 0.3 Newton (SD 0.2) times body weight when floor layers were kneeling back on the heels, to 3.5 Newton (SD 0.3) times body weight in the crawling work position. The study highlights the need for prevention by minimizing the amount of kneeling work positions among floor layers.

Migration of epoxidized soybean oil (ESBO) and phthalates from twist closures into food and enforcement of the overall migration limit.

Nineteen samples of food in glass jars with twist closures were collected by the national food inspectors at Danish food producers and a few importers, focusing on fatty food, such as vegetables in oil, herring in dressing or pickle, soft spreadable cheese, cream, dressings, peanut butter, sauces and infant food. The composition of the plasticizers in the gaskets was analysed by gas chromatography with flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC-MS). Epoxidized soybean oil (ESBO) and phthalates were determined in the homogenized food samples. ESBO was the principal plasticizer in five of the gaskets; in 14 it was phthalates. ESBO was found in seven of the food samples at concentrations from 6 to 100 mg kg(-1). The highest levels (91-100 mg kg(-1)) were in oily foods such as garlic, chilli or olives in oil. Phthalates, i.e. di-iso-decylphthalate (DIDP) and di-iso-nonylphthalates (DINP), were found in seven samples at 6-173 mg kg(-1). The highest concentrations (99-173 mg kg(-1)) were in products of garlic and tomatoes in oil and in fatty food products such as sauce béarnaise and peanut butter. For five of the samples the overall migration from unused lids to the official fatty food simulant olive oil was determined and compared with the legal limit of 60 mg kg(-1). The results ranged from 76 to 519 mg kg(-1) and as a consequence the products were withdrawn from the market.

Hip osteoarthritis: influence of work with heavy lifting, climbing stairs or ladders, or combining kneeling/squatting with heavy lifting.

The aim of the study was to evaluate the evidence for an association between hip osteoarthritis (OA) and physical work demands. Systematic searches were made and epidemiological studies on hip OA and heavy lifting, including farming and construction work and climbing stairs, were reviewed for the period 1966-2007 inclusive. The quality of the studies was assessed and best-evidence syntheses of a causal relation between hip OA and physical demanding work have been made using specific criteria of the different degrees of evidence of causality. Limitations of the studies include few participants, use of different diagnostic criteria, and a poor description of the exposure. It is concluded that moderate to strong evidence was found for a relation between heavy lifting and hip OA. The burdens have to be at least 10-20 kg and the duration at least 10-20 years to give a clearly increased risk of hip OA. For farmers the risk of hip OA seems doubled after approximately 10 years of farming and the evidence is considered as moderate to strong. The evidence for a relation between hip OA for construction workers is limited and there is insufficient or no evidence that climbing stairs or ladders causes hip OA.

Knee osteoarthritis: influence of work involving heavy lifting, kneeling, climbing stairs or ladders, or kneeling/squatting combined with heavy lifting.

The purpose of the study was to evaluate the evidence for an association between knee osteoarthritis (kneeOA) and physical work demands. Systematic searches were made, and epidemiological studies on kneeOA and heavy lifting, kneeling and climbing stairs published in 1966 to 2007 inclusive were reviewed. The quality of the studies was assessed and an overall evaluation of the degree of evidence of a causal relationship between kneeOA and physically demanding work was made, using specific criteria of the different degrees of evidence of causality. Limitations of the studies include few participants, use of different diagnostic criteria and a poor description of the exposure. It is concluded that moderate evidence was found for a relationship between kneeling, heavy lifting and kneeOA. For the combination of kneeling/squatting and heavy lifting the association seemed stronger than for kneeling/squatting or heavy lifting alone, but only a few studies were found concerning this relationship. Therefore the degree of evidence for a causal relationship was considered to be moderate. In the studies on the association between kneeOA and climbing stairs or ladders, there was an increased risk for kneeOA, but only a few studies were found and no dose-response relationship has been investigated. The evidence of a causal relationship is therefore considered to be limited.

Effects of training to implement new working methods to reduce knee strain in floor layers. A two-year follow-up.

OBJECTIVES: Follow-up study after two years to measure the effects of an implementation strategy consisting of information, education and training in the use of new tools and working-methods for the purpose of reducing knee strain and knee complaints in floor layers. METHODS: Training of floor layers (n = 292) in using new working methods was evaluated by questionnaires during the courses. Two years later, this follow-up included questionnaires for the course participants (n = 216) and a control group of floor layers (not trained on courses) (n = 454). RESULTS: Two years after training, 38% used the new working methods weekly or daily compared to 37% three months after the courses, and 10% before. Among controls, only 16% had used the new working methods weekly or daily. The risk of knee complaints >30 days (OR 2.46, 95% CI 1.03 to 5.83) or locking of the knees (OR 2.89, 95% CI 1.11 to 7.5) was more than double among floor layers who had used the new working-methods for less than one year compared to those who had used them more. The results were adjusted for age, body mass index, and stress. The reduction in more severe knee complaints was greatest if floor layers started to use the new working methods before they developed knee problems. Other musculoskeletal complaints did not increase. CONCLUSION: This indicates that, within a two-year perspective, the implementation strategy to introduce new working methods in the floor laying trade has been effective; the number of floor layers using the new working-methods has increased, and severe knee problems have reduced.

Carnitine transporter and holocarboxylase synthetase deficiencies in The Faroe Islands.

Carnitine transporter deficiency (CTD) and holocarboxylase synthetase deficiency (HLCSD) are frequent in The Faroe Islands compared to other areas, and treatment is available for both disorders. In order to evaluate the feasibility of neonatal screening in The Faroe Islands we studied detection in the neonatal period by tandem mass spectrometry, carrier frequencies, clinical manifestations, and effect of treatment of CTD and HLCSD. We found 11 patients with CTD from five families and 8 patients with HLCSD from five families. The natural history of both disorders varied extensively among patients, ranging from patients who presumably had died from their disease to asymptomatic individuals. All symptomatic patients responded favourably to supplementation with L: -carnitine (in case of CTD) or biotin (in case of HLCSD), but only if treated early. Estimates of carrier frequency of about 1:20 for both disorders indicate that some enzyme-deficient individuals remain undiagnosed. Prospective and retrospective tandem mass spectrometry (MS/MS) analyses of carnitines from neonatally obtained filter-paper dried blood-spot samples (DBSS) uncovered 8 of 10 individuals with CTD when using both C(0) and C(2) as markers (current algorithm) and 10 of 10 when using only C(0) as marker. MS/MS analysis uncovered 5 of 6 patient with HLCSD. This is the first study to report successful neonatal MS/MS analysis for the diagnosis of HLCSD. We conclude that CTD and HLCSD are relatively frequent in The Faroe Islands and are associated with variable clinical manifestations, and that diagnosis by neonatal screening followed by early therapy will secure a good outcome.

Health evaluation of volatile organic compound (VOC) emissions from wood and wood-based materials.

In this study, the authors describe a method for evaluation of material emissions. The study was based on chemical analysis of emissions from 23 materials representing solid wood and wood-based materials commonly used in furniture, interior furnishings, and building products in Denmark in the 1990s. The authors used the emission chamber testing method to examine the selected materials with a qualitative screening and quantitative determination of volatile organic compounds. The authors evaluated the toxicological effects of all substances identified with chamber testing. Lowest concentration of interest and standard room concentrations were assessed, and the authors calculated an S-value for each wood and wood-based material. The authors identified 144 different chemical substances with the screening analyses, and a total of 84 individual substances were quantified with chamber measurements. The irritative effects dominated at low exposure levels; therefore, the lowest concentration of interest and the S-value were based predominantly on these effects. The S-values were very low for solid ash, oak, and beech. For solid spruce and pine, the determining substances for size of the S-value were delta3-carene, alpha-pinene, and limonene. For the surface-treated wood materials, the S-value reflected the emitted substances from the surface treatment.

Work-related knee disorders in floor layers and carpenters.

Previous studies indicate an increased prevalence of knee disorders in some occupations possibly related to kneeling working positions. The purpose of the present study was to examine the relationship among knee-straining work, self-reported knee-complaints, and physical signs of knee disorders. The duration of knee-straining work was estimated from videotapes of representative work tasks. Floor layers (n = 133), carpenters (n = 506), and compositors (n = 327) aged 26 to 72 years without previous acute knee traumas were examined in a cross-sectional study by questionnaire. A stratified random sample of the questionnaire responders; 67 floor layers, 127 carpenters, and 101 compositors had independent double examinations for physical signs of knee disorders. The videotapes showed that knee-straining work constituted 56% of working time for floor layers, 26% for carpenters, and none for compositors. The prevalences of self-reported knee-complaints were positively associated with the amount of knee-straining work and were significantly different for the three trades. Floor layers and carpenters who were presently working in their trade had a higher prevalence of knee complaints than floor layers and carpenters who had left their trade. Age, seniority, weight, body mass index, smoking, and knee-straining sports activity had no significant effects. The clinical study showed a positive association for knee-straining work, hyperkeratosis, and bursitis. A similar pattern was found for signs of intraarticular knee disorders by one physician but not by another. The reproducibility of these signs was low. More studies are needed to define clinically important knee disorders for epidemiological studies.

Radiographic knee osteoarthritis in floorlayers and carpenters.

OBJECTIVES: The aim of the present study was to examine the relationship between knee-straining work and radiological findings of knee osteoarthritis and to study the relation between radiological findings and self-reported knee complaints and clinical signs of knee osteoarthritis. METHODS: The material consisted of 133 floorlayers, 506 carpenters, and 327 compositors, 26-72 years of age, who had completed a questionnaire and reported no previous knee trauma. A stratified sample of these questionnaire respondents, 50 floorlayers, 51 carpenters, and 49 compositors, were radiologically examined for knee osteoarthritis by 2 radiologists. The X-ray films were independently assessed by 2 radiologists and blinded with respect to knee complaints, trade, and age. RESULTS: The radiological investigation showed estimated prevalences of knee-osteoarthritis (grades 2-4) for 14% of the floorlayers, 8% of the carpenters, and 6% of the compositors (not significantly different). For the subjects > or =50 years of age the estimated prevalences of the combination of radiological grades 2-4 for knee osteoarthritis and knee complaints during the last 12 months were 29% [95% confidence interval (95% CI) 17-44%], 9% (95% CI 1-26%), and 1% (95% CI 1-10%) for the floorlayers, carpenters, and compositors, respectively. Radiological grades 2-4 were mainly found for subjects above the age of 50 years, subjects with knee complaints, and floorlayers. Radiological knee osteoarthritis was positively associated with self-reported knee complaints and with clinical signs of intraarticular and retropatellar crepitation. CONCLUSIONS: The data suggest that work in which a considerable amount of time is spent in knee-straining positions may be a risk factor for the development of knee osteoarthritis above the age of 50 years.

Validity of self-reporting and video-recording for measuring knee-straining work postures.

The aim of this study was to compare the validity of self-reporting and video-recording as methods of measuring the duration of knee-straining work postures, and to evaluate the reproducibility of timings of the video-recordings. Thirty-nine carpenters and 33 floorlayers were video-filmed while working, and were asked immediately afterwards to quantify the amount of time spent in knee-straining positions. The investigators recorded the periods of knee-straining work with a stopwatch during playback of the video-film, and the agreement between the two investigators' measurements was studied in 13 pairs of measurements. The video-observation method was very effective for timing knee-strain work. Furthermore, Spearman's correlation coefficient (0.88) indicated a good association between observed and self-reported knee-straining work. Estimation of self-reported knee-straining work collected by interview showed good correlation with measurements of video-recordings. When judging the repeatability of timings of knee-straining work from the video-recordings, a high level of agreement was seen between the two observers in the 13 dual measurements of time spent in knee-straining work positions.

[Relationship between occupation and elbow pain, epicondylitis]. / Sammenhaeng mellem erhverv og albuesmerter, epicondylitis.

Twelve controlled epidemiological studies describing the relationship between epicondylitis and work were found. The studies showed evidence for an association between forceful work and a combination of repetition and forceful work and development of elbow pain, epicondylitis. No controlled studies showing an association between work with visual display units or use of computer mouse and epicondylitis were found. No relationship was found between unaccustomed work and development of epicondylitis. Age and time spent in the employment seem to be disposing factors. Generally the studies did not distinguish between medial and lateral epicondylitis. The studies were characterized by small study populations. Further research including quantitative evaluation of exposure factors and patophysiology is needed.

Occupation as a risk factor for knee disorders.

The objective of the present study was to review the literature on the risk of knee disorders in connection with kneeling or squatting work and heavy physical work. A systematic review of the literature revealed 19 controlled studies on this correlation: 16 on osteoarthrosis, 5 on bursitis, 3 on meniscal lesions, and 0 on chondromalacia. All the studies demonstrated a significantly increased prevalence of knee osteoarthrosis (all degrees) for subjects with kneeling or squatting work. The prevalence ratio in most of these studies was between 1.4 and 4. Four of eight studies demonstrated a significantly increased prevalence of knee osteoarthrosis in subjects with heavy physical work. The prevalence ratio in most of these studies was between 1.4 and 4.1. All the studies on bursitis showed an increased prevalence of bursitis in subjects with kneeling work. Occupational exposure could not be sufficiently documented as the cause of meniscal lesions and chondromalacia.

Bis-intercalation of a homodimeric thiazole orange dye in DNA in symmetrical pyrimidine-pyrimidine-purine-purine oligonucleotides.

One- and two-dimensional 1H NMR spectroscopy were used to characterize the binding of a homodimeric thiazole orange dye, 1,1'-(4,4,8,8-tetramethyl-4,8-diazaundecamethylene)-bis-4-(3 -methyl-2,3-dihydro-(benzo- 1,3-thiazole)-2-methylidene)-quinolinium tetraiodide (TOTO), to various double-stranded DNA oligonucleotides containing symmetric (5'-pyr-pyr-pu-pu-3')2 or (5'-pu-pu-pyr-pyr-3')2 sequences. It was found that TOTO binds preferentially to oligonucleotides containing a (5'-CTAG-3')2 or a (5'-CCGG-3')2 sequence. Binding to the (5'-CCGG-3')2 sequence is less favored than to the (5'-CTAG-3')2 sequence. The complexes of TOTO with d(CGCTAGCGCTAGCG)2 (10) and d(CGCTAGCCGGCG):d(CGCCGGCTAGCG) (11) oligonucleotides, each containing two preferential binding sites, was also examined. In both cases TOTO forms mixtures of 1:1 and 1:2 dsDNA-TOTO complexes in ratios dependent on the relative amount of TOTO and the oligonucleotides in the sample. Binding of TOTO to the two oligonucleotides is sequence selective at the (5'-CTAG-3')2 and (5'-CCGG-3')2 sites. The 1H NMR spectra of both the 1:2 complexes and the three different 1:1 complexes have been assigned. A slight negative cooperativity is observed in formation of the 1:2 complexes. The ratio between the two different 1:1 complexes formed with oligonucleotide 11 is 2.4 in favor of binding to the (5'-CTAG-3')2 site. This is very similar to results obtained when the two sites are in different oligonucleotides. Thus the distribution of TOTO among the (5'-CTAG-3')2 and (5'-CCGG-3')2 sites is independent of whether the two sites are in the same or two different oligonucleotides.

[Side-effects and doping control of anabolic steroids]. / Bivirkninger og dopingkontrol ved brug af anabole steroider.

We present a case of a 26 year-old male body-builder who had used the anabolic steroids (AS) trenbolone and stanozolol for 10 weeks. After four weeks creatine-kinase (CK) including CK-B (cardiac specific isoenzymes) levels were elevated five to ten times. He was without cardiac symptoms and electrocardiography was normal. Three weeks after he stopped using AS, CK and CK-B levels had normalized. One of the drugs, stanozolol could not be detected by the doping-control, maybe because of a fast excretion time. Sale, use and delivery of AS is prohibited in Denmark, but is used in spite of the prohibition. It is important to spread knowledge about the risks of AS among the users.

Modifications of health behaviour in response to air pollution notifications in Copenhagen.

Ambient air quality is a major issue today in large cities all over the world. On the theoretical background of the health belief model and the health locus of control model, we studied the knowledge and beliefs about air pollution and the modifications of health behaviour brought about by information to the public about projected levels of air pollution, with special emphasis on reduction of outdoor activity and avoidance of car driving. Data were collected with a questionnaire among a sample of residents in the Copenhagen area. The respondents were almost universally knowledgeable about the prime emission source and concerned about the possible health effects of the air pollution in the area. Avoidance of outdoor activity was associated with personal experiences of symptoms ascribed to the air pollution, employment status, and with female sex, but not with knowledge or beliefs about the degree or health implications of the air pollution. The willingness to avoid car driving was positively associated with the belief that one can oneself influence one's health and with female sex. Lung diseased respondents were generally more prone to protect themselves than the healthy, both by avoiding outdoor activity and by being less willing to avoid car driving. The present study was conducted in an only moderately polluted city, and it is not clear whether the findings and conclusions can be generalized to more polluted cities. The study partly supported the underlying theories of the determinants of health behaviour, but also indicated a need for a broader theoretical framework, incorporating aspects of the respondents' life situation and personal experience which would be relevant to the specific type of health behaviour under study.