Whiplash-associated disorders impairment rating: neck disability index score according to severity of MRI findings of ligaments and membranes in the upper cervical spine

The aim of this study was to explore whether reported pain and functional disability in whiplash-associated disorders (WAD) patients is associated with lesions to specific soft tissue structures in the upper cervical spine, as assessed by MRI. Pre-selected structures for MRI assessment included the alar ligaments, the transverse ligament, the tectorial and the posterior atlanto-occipital membranes. The questionnaire employed was a modification of the Oswestry Low Back Pain Index. It was comprised of ten single items related to pain and activity of daily living. Ninety-two whiplash patients and 30 control persons, randomly drawn, were included. WAD patients reported significantly more pain and functional disability than the controls, both for total score and each of the ten single items. In the WAD patients, MRI lesions to the alar ligaments showed the most consistent association to the reported pain and disability. Lesions to other structures often occurred in combination with lesions to the alar ligaments. Lesions to the transverse ligament and to the posterior atlanto-occipital membrane also appeared to be related to the NDI score, although the association was weaker than for the alar ligament. The disability score increased with increasing number of abnormal (grade 2-3) structures. These results indicate that symptoms and complaints among WAD patients can be linked with structural abnormalities in ligaments and membranes in the upper cervical spine, in particular the alar ligaments.     

Health services research in oral health care: an empirical example.

Health services research is mainly applied research which can contribute to the production of knowledge necessary to appropriate decisions in health care. As an example, a study of the occurrence of tooth extractions is presented. Two hypotheses were tested: a negative relationship between provider density and consumer income, and the probability of tooth extractions and the number of teeth extracted, conditional upon extraction. A nationwide sample of 1286 non-institutionalized Norwegians 20 yr and above was interviewed by a public survey institute. The data were analyzed using a two-part model including logistic regression and multiple regression analysis. One third of the sample had had a tooth extraction during the last 5 yr. The majority of the sample had few teeth extracted at the time of extraction. The probability of tooth extraction was related to provider density and not to consumer income. The number of teeth extracted was related neither to provider density nor to income. Tooth extraction was not related to age. Some policy implications are discussed.     

Type of contract and supplier-induced demand for primary physicians in Norway

The focus of the present study is to examine whether supplier-induced demand exists for primary care physician services in Norway. We compare how two groups of physicians, with and without incentives to induce, respond to increased competition. Contract physicians receive their income from fee-for-item payments. They have an incentive to compensate for a lack of patients by inducing demand for services. Salaried physicians receive a salary which is independent of output. Even though increased competition for patients reduces the availability of patients, they have no financial incentive to induce. Neither of the two groups of physicians increased their output as a response to an increase in physician density. This result could be expected for salaried physicians, while it provides evidence against the inducement hypothesis for contract physicians.     

Equity in access to public dental services: the experience from Norway

The aim of this study was to identify possible factors associated with the marked geographical variation in supply of public dental services in Norway. We identified three sources for this uneven distribution: differences in dental care needs, differences in revenue levels between counties, and differences in the party composition of the county councils. Analyses were undertaken to ascertain whether these factors were related to the variation in the number of man-labor years of public dental officers. The analyses were performed on a set of data from Norwegian counties for the period 1985-92. There was an association between the number of man-labor years of public dental officers and our indicators of dental care needs, county revenue, and party composition of the county councils. Our findings are encouraging, as they indicate that the county councils seemed to respond to the dental care needs of the local population. On the other hand, there were inequalities in supply of public dental services that were due to differences in revenue between counties. From an equity point of view, this inequality is undesirable. The inequality could most likely be reduced by decreasing the variation in revenue between counties. Differences in party composition of the county councils had only a small effect on the geographical variation in the number of man-labor years of public dental officers.     

The effect of attending a flexible sigmoidoscopic screening program on the prevalence of colorectal adenomas at 13-year follow-up

OBJECTIVES: Understanding the epidemiology of colorectal adenomas is a prerequisite for designing follow-up programs after polypectomy. The aim of the study was to investigate the effect of polypectomy on the long-term prevalence of adenomas. METHODS: In 1983, a total of 799 men and women aged 50-59 yr were drawn from the general population register. Of these, 400 comprised a screening group and 399 a matched control group. The screenees were invited to undergo a once-only flexible sigmoidoscopy. Persons with polyps had a baseline colonoscopy with follow-ups in 1985 and 1989. In 1996, both the screenees and the controls were invited to a colonoscopic examination. RESULTS: In 1996, a total of 451 (71%) individuals attended. Adenomas were found in 78 (37%) individuals in the screening group and 103 (43%) in the control group, relative risk (95% confidence interval): 0.9 (0.7-1.1), p = 0.3, and high-risk adenomas (severe dysplasia, adenomas > or = 10 mm, villous components) were found in 16 (8%) and 32 (13%), respectively; relative risk (95% confidence interval): 0.6 (0.3-1.0), p = 0.07. CONCLUSIONS: There was no significant difference in adenoma prevalence between the group after the screening program and the controls after the usual care. There was a trend toward more high-risk adenomas in the control group. This suggests a very limited effect of one-time screening sigmoidoscopy with surveillance colonoscopy on the prevalence of adenomas, but a preventive effect on the development of high-risk adenomas consistent with the reported effect on cancer prevention.     

The impact of education on dental health — Ways to measure causal effects

To our knowledge, there are no studies in which a possible causal effect of education on dental health has been examined. Such studies are needed to predict whether more schooling for people with poor dental health improves their dental health. Within social science, and in economics in particular, several methods have been developed to make causal inferences of the relationship between education and general health. These methods, which are based on observational data, are relevant to use for estimating a possible causal effect of education on dental health. This commentary provides an overview of the state of the art of the following methods: the use of instrumental variables, twin studies and a regression discontinuity design. Using these methods, reversed causality and the omission of a third variable that influences both education and dental health can be controlled for. In that way, an unbiased estimate of the effect of education on dental health can be obtained. To implement each of the methods correctly, several criteria have to be fulfilled. These criteria are outlined and discussed below.