Biomedical subjects

Christoffer Johansen

Publications and source records attributed to Christoffer Johansen.

At least 19 recordsLinked to original sources

PubMed2007

Mobile phone use and risk of glioma in 5 North European countries.

Public concern has been expressed about the possible adverse health effects of mobile telephones, mainly related to intracranial tumors. We conducted a population-based case-control study to investigate the relationship between mobile phone use and risk of glioma among 1,522 glioma patients and 3,301 controls. We found no evidence of increased risk of glioma related to regular mobile phone use (odds ratio, OR = 0.78, 95% confidence interval, CI: 0.68, 0.91). No significant association was found across categories with duration of use, years since first use, cumulative number of calls or cumulative hours of use. When the linear trend was examined, the OR for cumulative hours of mobile phone use was 1.006 (1.002, 1.010) per 100 hr, but no such relationship was found for the years of use or the number of calls. We found no increased risks when analogue and digital phones were analyzed separately. For more than 10 years of mobile phone use reported on the side of the head where the tumor was located, an increased OR of borderline statistical significance (OR = 1.39, 95% CI 1.01, 1.92, p trend 0.04) was found, whereas similar use on the opposite side of the head resulted in an OR of 0.98 (95% CI 0.71, 1.37). Although our results overall do not indicate an increased risk of glioma in relation to mobile phone use, the possible risk in the most heavily exposed part of the brain with long-term use needs to be explored further before firm conclusions can be drawn.

Adolescent↗

PubMed2007

A comparison of self-reported cellular telephone use with subscriber data: agreement between the two methods and implications for risk estimation.

Epidemiologic studies on adverse health effects of cellular telephone use have assessed exposure either by self-reported use based on questionnaire data or by using data on subscriptions for a cellular telephone provided by network operators. With the latter approach, subjects are misclassified when they regularly use a cellular telephone subscribed in someone else's or in a company name or when they subscribe for a cellular telephone which they use only occasionally. Self-reported use is hampered by recall difficulties and possible differential participation by exposure. In Denmark, we conducted a retrospective cohort study of cellular telephone subscribers (including the entire Danish population) and a case-control study on brain tumors and cellular telephone use (with 1355 participants) and, thus, had the opportunity to compare the two exposure measures with two large-scale data sets, using self-reported use as a "gold standard." Overall, there was a fair agreement (kappa value of 0.30, 95% confidence interval 0.23-0.36), with a low sensitivity (30%) and a high specificity (94%). Agreement was slightly better for controls, and low-grade glioma cases compared to high-grade glioma cases and meningioma cases. A comparison of odds ratios (OR) of the case-control data set based on either self-reported use or on subscriber data shows no major differences, giving OR of 0.7 and 0.6 for acoustic neuroma, 0.9 and 1.1 for glioma and 0.9 and 0.7 for meningioma. A discussion of the two exposure measures reveals that they both have limitations with regard to a potential underestimation of an association and there is some concern whether they are good enough to allow a detection of possibly only subtle changes in risk. These limitations can be minimized in prospective follow-up studies.

Cell Phone↗

PubMed2006

Genetic variation in p53 and ATM haplotypes and risk of glioma and meningioma.

BACKGROUND: P53 and ATM are central checkpoint genes involved in the repair of DNA damage after ionising irradiation, which has been associated with risk of brain tumours. Therefore, we tested the hypothesis that polymorphisms and haplotypes in p53 and ATM could be associated with glioma and meningioma risk. MATERIAL AND METHODS: Six hundred and eighty glioma cases (298 glioblastoma (GBM)), 503 meningioma cases, and 1555 controls recruited in the Nordic-UK Interphone study, were analysed in association with three polymorphisms in p53 (rs2287499, rs1042533, rs1625895) and five polymorphisms in ATM ( rs228599, rs3092992, rs664143, rs170548, rs3092993). Haplotypes were constructed using the HAPLOSTAT program. RESULTS: The global statistical test of glioblastoma and p53 haplotypes was p = 0.02. The haplotype analysis on glioblastoma revealed the 1-2-2 haplotype (promotor-codon72-intron 6) had a frequency of 6.1% in cases compared with 9.8% in controls (p = 0.003). The 1-2-1 haplotype was significantly more frequent in GBM cases, 10.2%, than in controls, 7.3% (p = 0.02). The haplotype analysis in ATM revealed an increased frequency of the 1-1-1-2-1 haplotype in meningioma cases (33.8%) compared with controls (30.3%) (p = 0.03). The 2-1-2-1-1 haplotype had a lower frequency in meningioma cases (36.1%) than controls (40.7%) (p = 0.009). CONCLUSIONS: This study found both positive and negative associations of haplotypes in p53 for glioblastoma and ATM for meningioma. This study provides new data that could add to our understanding of brain tumour susceptibility.

Adult↗

PubMed2006

Cellular telephone use and cancer risk: update of a nationwide Danish cohort.

BACKGROUND: The widespread use of cellular telephones has heightened concerns about possible adverse health effects. The objective of this study was to investigate cancer risk among Danish cellular telephone users who were followed for up to 21 years. METHODS: This study is an extended follow-up of a large nationwide cohort of 420,095 persons whose first cellular telephone subscription was between 1982 and 1995 and who were followed through 2002 for cancer incidence. Standardized incidence ratios (SIRs) were calculated by dividing the number of observed cancer cases in the cohort by the number expected in the Danish population. RESULTS: A total of 14,249 cancers were observed (SIR = 0.95; 95% confidence interval [CI] = 0.93 to 0.97) for men and women combined. Cellular telephone use was not associated with increased risk for brain tumors (SIR = 0.97), acoustic neuromas (SIR = 0.73), salivary gland tumors (SIR = 0.77), eye tumors (SIR = 0.96), or leukemias (SIR = 1.00). Among long-term subscribers of 10 years or more, cellular telephone use was not associated with increased risk for brain tumors (SIR = 0.66, 95% CI = 0.44 to 0.95), and there was no trend with time since first subscription. The risk for smoking-related cancers was decreased among men (SIR = 0.88, 95% CI = 0.86 to 0.91) but increased among women (SIR = 1.11, 95% CI = 1.02 to 1.21). Additional data on income and smoking prevalence, primarily among men, indicated that cellular telephone users who started subscriptions in the mid-1980s appeared to have a higher income and to smoke less than the general population. CONCLUSIONS: We found no evidence for an association between tumor risk and cellular telephone use among either short-term or long-term users. Moreover, the narrow confidence intervals provide evidence that any large association of risk of cancer and cellular telephone use can be excluded.

Cell Phone↗

PubMed2006

Quality of life of Danish colorectal cancer patients with and without a stoma.

GOALS OF THE WORK: As part of a psychosocial intervention study, we wanted to prospectively assess the quality of life of colorectal cancer patients who were given a stoma at the time of their initial operation for cancer or later and those whose initial stoma was removed. MATERIALS AND METHODS: A total of 249 colorectal cancer patients were recruited and responded to a questionnaire 3, 6, 12 and 24 months after the initial operation (26-35% had a stoma during follow-up). MAIN RESULTS: Although most of the differences between stoma and non-stoma patients failed to reach significance, 22 out of 27 variables indicated a poorer quality of life for those with a stoma. Patients who currently had a stoma had significantly higher levels of depression (p = 0.013), poorer social functioning (p = 0.0085) and more problems with body image (p = 0.0001), future perspectives (p = 0.0058), micturition (p = 0.018) and side effects from chemotherapy (p = 0.008), but fewer problems with constipation (p = 0.034) than non-stoma patients. Male patients with a stoma had more sexual problems than males without a stoma (p = 0.015). Among those with a current stoma, quality of life seemed poorer among those whose stoma was made during follow-up compared with those with an initial stoma. CONCLUSIONS: Trends suggested that having a stoma led to poorer scores in most aspects of quality of life and that having a stoma made some time after the initial operation was more distressing than having a stoma made during the primary cancer operation.

Aged↗

PubMed2006

Psychometric properties of brief indexes designed to measure social-cognitive predictors of smoking initiation.

BACKGROUND: Constructing indexes which measure factors that may predict smoking initiation is essential for planning prevention programs. Our aim was to examine the criterion-related construct validity of brief psychological indexes of attitude, social influence and self-efficacy to be used in future studies for predicting smoking initiation in adolescents. METHODS: Five indexes were evaluated using cross-sectional data on 4819 adolescents age 13 in a random sample of schools in six Danish counties. Item analyses were performed with the graphical log-linear Rasch model, a modification of the Rasch model that allows for differential item functioning and positive local dependence. RESULTS: The three indexes social influence-norms, social influence-pressure and attitude showed acceptable deviations from the Rasch model, while the two indexes self-efficacy and social influence-behavior were invalidated by negative local dependence. CONCLUSION: Of the five tested indexes, three (social influence-norms, social influence-pressure and attitude) showed acceptable criterion-related construct validity and may be considered unbiased representations of the theory-based factors if statistical analyses are appropriately adjusted. The results of this population-based study show that the graphical log-linear Rasch model is useful for evaluating health-related behavior indexes and identifying problems, which can be dealt with when using the indexes in future studies.

Adolescent↗

PubMed2006

Does marital status and altered contact with the social network predict colorectal cancer survival?

We examined whether changes in the frequency of contact with the social network (partner, children, grandchildren, other relatives, friends and colleagues) in a group of colorectal cancer patients were associated with survival. The study was based on a questionnaire survey from 1991. The study population consisted of 770 Danish colorectal cancer patients diagnosed in the period 1985-1990, and followed up for survival until March 2002. Using Cox regression analysis we found a significantly higher mortality among patients who had lost their partner before the operation compared to patients cohabiting with the same partner as before the operation (rate ratio (RR)=1.4, 95% confidence interval (CI): 1.1-1.8) possibly because of less active cancer treatment. This needs investigation in future studies. Contrary to expectations we also found a significantly higher mortality among patients reporting increased contact with their children compared to patients reporting unchanged contact frequency (RR=1.7, 95% CI: 1.3-2.4). However, a low physical functioning of the cancer patient may have confounded the latter result.

Adolescent↗

PubMed2006

Mobile phone use and risk of parotid gland tumor.

Handheld mobile phones were introduced in Denmark and Sweden during the late 1980s. This makes the Danish and Swedish populations suitable for a study aimed at testing the hypothesis that long-term mobile phone use increases the risk of parotid gland tumors. In this population-based case-control study, the authors identified all cases aged 20-69 years diagnosed with parotid gland tumor during 2000-2002 in Denmark and certain parts of Sweden. Controls were randomly selected from the study population base. Detailed information about mobile phone use was collected from 60 cases of malignant parotid gland tumors (85% response rate), 112 benign pleomorphic adenomas (88% response rate), and 681 controls (70% response rate). For regular mobile phone use, regardless of duration, the risk estimates for malignant and benign tumors were 0.7 (95% confidence interval: 0.4, 1.3) and 0.9 (95% confidence interval: 0.5, 1.5), respectively. Similar results were found for more than 10 years' duration of mobile phone use. The risk estimate did not increase, regardless of type of phone and amount of use. The authors conclude that the data do not support the hypothesis that mobile phone use is related to an increased risk of parotid gland tumors.

Adult↗

PubMed2006

Development in incidence of breast cancer in non-screened Danish women, 1973-2002--a population-based study.

The authors report on the incidence rates of breast cancer overall and by histology in a population of unscreened women constituting approximately 80% of the total population of women in Denmark from 1973-2002, utilizing the files of the nationwide Danish Cancer Registry. The age-specific incidence rates of breast cancer increased throughout the period, and further, marked changes in the age-specific incidence pattern were observed, where the plateau and change of slope around the age of 46-48 in 1973-1981 shifted to around age 64-66 years in 1994-2002. Age-period-cohort modeling indicated that these changes were not attributable to a birth cohort effect. Although lobular breast cancer incidence increased more than ductal breast cancer incidence, this was only observed in the first decade after the introduction of the ICD-O system in Denmark and probably is attributable to this, whereas we observed no disproportionate changes by histology in any age group from 1988-2002. Thus, previous reports of a disproportionate increase in lobular breast cancer could not be confirmed in a non-screened population, whereas important changes over the past decade in the age-specific incidence pattern of breast cancer particular around the time of menopause were indicated.

Age Factors↗

PubMed2006

Leaving home after cancer in childhood: a measure of social independence in early adulthood.

BACKGROUND: Previous studies on psychosocial outcomes for childhood and adolescent cancer survivors have found diverse results concerning social independence. As a measure of social independence, we investigated whether cancer survivors displayed the same patterns of leaving home as population-based control group. PROCEDURE: We identified 1,597 patients in the Danish Cancer Register, born in 1965-1980, in whom a primary cancer was diagnosed before they reached the age of 20 in the period 1965-1995. The patients were compared with a random sample of the general population (n = 43,905) frequency matched on sex and date of birth. By linking the two cohorts to registers in Statistics Denmark, we obtained socioeconomic data for the period 1980-1997. The relative risk for leaving home was estimated with discrete-time Cox regression models. RESULTS: The risk for leaving home of survivors of hematological malignancies and solid tumors did not differ significantly from that of the control cohort. Adjustments for possible socioeconomic confounders did not change this pattern. In contrast, survivors of central nervous system (CNS) tumors had a significantly reduced risk for leaving home, which was most pronounced for men (relative risk, men: 0.66; 95% confidence interval, 0.55-0.80; women: 0.88, 95% confidence interval, 0.80-0.97). CONCLUSION: Overall, the psychosocial effects of cancer in childhood or adolescence and its treatment on the survivor and family did not appear to impede social independence in early adulthood, except for survivors of CNS tumors.

Adolescent↗

PubMed2006

Mental vulnerability--a risk factor for ischemic heart disease.

OBJECTIVE: The purpose of this study is to examine whether mental vulnerability is a risk factor for the development of ischemic heart disease (IHD) after adjustment for well-established risk factors. METHODS: In three prospective cohort studies in Copenhagen County, Denmark, we recorded the level of mental vulnerability and possible risk factors to IHD at baseline. For follow-up, the sample was linked to relevant registries to identify all cases of fatal and nonfatal IHD. The relationship between mental vulnerability and IHD was examined using both Kaplan-Meir and Cox proportional hazard models adjusting for possible confounding factors. RESULTS: Mental vulnerability was significantly associated with the risk for IHD (medium mental vulnerability: hazard ratio 1.41, 95% confidence interval 1.04-1.91; and high mental vulnerability: hazard ratio 2.05; 95% confidence interval 1.46-2.88), after adjusting for confounders. CONCLUSION: Our results imply that mental vulnerability is an independent risk factor for IHD.

Adult↗

PubMed2006

Body composition and breast cancer in postmenopausal women: a Danish prospective cohort study.

OBJECTIVE: To assess the importance of body fat mass (BFM) and fat free mass (FFM) for the established positive association between BMI and breast cancer among post-menopausal women. RESEARCH METHODS AND PROCEDURES: A prospective cohort of 23,788 postmenopausal women included in the Danish study Diet, Cancer, and Health during 1993 to 1997 was linked to the Danish Cancer Registry to identify all cases of breast cancer occurring during 1993 to 2002. Breast cancer incidence rate ratios for anthropometric measurements with adjustment for known risk factors for breast cancer were calculated by Cox regression analyses. RESULTS: Among the most commonly used anthropometric measurements, BMI was positively associated with breast cancer among never users of hormone replacement therapy (HRT). By splitting BMI into two indices, BFM index and FFM index, we found that the incidence rate ratio with each 1 kg/m(2) among never users of HRT was 0.98 (95% confidence interval, 0.93 to 1.03) for BFM index and 1.12 (95% confidence interval, 1.00 to 1.26) for FFM index after mutual adjustment. DISCUSSION: The finding for BMI was in accordance with previous findings. Our results indicate that the FFM component of BMI may play a role for development of breast cancer among never users of HRT.

Adipose Tissue↗

PubMed2006

Iodine intake and incidence of thyroid cancer in Denmark.

OBJECTIVE: Iodine intake is suspected to be a risk factor for thyroid cancer. Eastern Denmark is characterized by mild and western Denmark by moderate iodine deficiency, and this difference is associated with a 50% difference in the occurrence of goitre and thyrotoxicosis. The objective of the study was to determine whether the incidence of thyroid cancer differs between these two regions, as any difference would have important safety implications for the national iodine supplementation programme. DESIGN AND METHODS: We studied all thyroid cancers notified to the Danish Cancer Registry in the period 1973-1997, focusing on the four most frequent subtypes: papillary, follicular, anaplastic and medullary thyroid cancer. A Poisson regression model was used with models of goodness-of-fit for age, period, sex. RESULTS: No regional difference was found in the overall incidence of follicular (0.3% 100 000 person-years) or papillary (0.7% 100 000 person-years) thyroid cancer. A slight but nonsignificant increase in total incidence, resulting mainly from a significant increase in the incidence for the papillary subtype, was observed in both regions. CONCLUSION: The results suggest that modest differences in iodine intake do not affect thyroid cancer incidence or the distribution of subtypes.

Adenocarcinoma, Follicular↗

PubMed2006

Risk of cancer in children with the diagnosis immaturity at birth.

Cancer risk in children born before term has been assessed in a large number of case-control studies but very rarely in cohort studies. We carried out a cohort study of 35 178 children with the diagnosis immaturity at birth in the Hospital Discharge Register during 1977-89. The children were followed for cancer in the Danish Cancer Registry until 1994 and comparisons were made with incidence rates for all children in Denmark. The 64 observed cases of childhood cancer in the cohort corresponded closely to the expected number {standardised incidence ratio (SIR) = 1.03; [95% confidence interval (CI) 0.80, 1.32]}. The only cancer site with an observed number that deviated significantly from the expected number was central nervous system (CNS) tumours (26 cases observed; SIR = 1.57; [95% CI 1.02, 2.30]) in particular medulloblastoma (9 cases observed; SIR = 3.1; [95% CI 1.4, 5.9]). In a nested case-control study of the CNS tumours, we found that more cases than controls had been exposed to diagnostic X-rays, but the result was not significant. Surprisingly, for those born before term, the risk of CNS tumours increased with increasing gestational age in the nested case-control data. Our results are in line with previous evidence that children born before term are not at increased risk for childhood cancer in general. An explanation behind the excess of CNS tumours could not be identified, but the effect of diagnostic X-rays in newborns may deserve further attention.

Adolescent↗

PubMed2006

SSRIs and upper gastrointestinal bleeding: what is known and how should it influence prescribing?

SSRIs have achieved a high usage rate in the treatment of depression because of a similar efficacy to TCAs and a favourable safety and tolerability profile. However, SSRI use has been associated with bleeding. We reviewed the epidemiological evidence on the association between SSRI use alone and the risk of upper gastrointestinal bleeding, and on synergistic effects reported with other commonly used drugs that can also cause bleeding.A literature search identified four studies of SSRI use and risk for upper gastrointestinal bleeding and a further two studies of SSRI use and bleeding in general, including upper gastrointestinal bleeding. The available evidence indicates quite convincingly that SSRI use may play a causal role in upper gastrointestinal bleeding and that these drugs may act synergistically with other bleeding risk-increasing medications such as NSAIDs or low-dose aspirin. Assuming a causal role of SSRIs, reported excess gastrointestinal bleedings attributable to SSRI use was reported to be 3.1 per 1000 treatment years, 4.1 per 1000 treatment years among octogenarians and 11.7 per 1000 treatment years among persons with prior upper gastrointestinal bleeding. These non-negligible risks warrant that prescribing doctors consider strategies on the individual level to reduce the likelihood of an upper gastrointestinal adverse event. Patients at particular risk include those with previous ulcers or gastrointestinal bleeding, the elderly and those with certain concurrent illnesses and/or high-risk comedications. Suggested strategies include alternatives to SSRI use, prescribing of less gastrotoxic NSAIDs or co-prescribing of gastroprotective drugs. Patients should be informed about the likelihood of possible upper gastrointestinal bleeding and high-risk patients should be followed closely.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed2005

Incidence of intracranial meningiomas in Denmark, Finland, Norway and Sweden, 1968-1997.

It has been reported that the incidence of meningioma increased in several industrialized countries in the late 1970s and early 1980s. The aim of this study was to evaluate the time trends in incidence of meningiomas in Denmark, Finland, Norway and Sweden, with emphasis on the age distribution and sex ratio. Information about cases of meningiomas in people aged 15-84 years was obtained from the cancer registries of these Nordic countries for the years 1968-1997, and estimates of person-years at risk were calculated from information provided by the national population registries. Age-specific incidence rates per 100,000 and incidence rate ratios were calculated for 3-year periods. The female:male ratios were also evaluated. The combined incidence among men increased from 1.4 to 1.9 per 100,000 during the follow-up period, the corresponding rates for women were 2.6 and 4.5. The female:male ratio increased over time for several age groups and was as high as 3.5:1 in the group aged 40-44 years in the latest follow-up period (1993-1997). In summary, our results provide some support for the idea that the introduction of computed tomography in the late 1970s has had an impact on the detection of cases in people aged 60 and over. The decrease in the rate or detection postmortem has affected the incidence time trend, but it also coincides with widespread use of new imaging technologies. The increasing trend shown for the female:male ratio in the group aged 35-59 years is consistent with the possibility that increasing use of hormones may affect the incidence of meningiomas in women.

Adolescent↗

PubMed2005

Trends in testicular cancer incidence in the Nordic countries, focusing on the recent decrease in Denmark.

Testicular cancer is the most frequent malignancy among young men, and there have been steady increases in its incidence in most western countries for many decades. Recently, a decrease was seen in some countries, including Denmark. Here, we report recent trends in testicular cancer incidence in the Nordic countries. We address the hypothesis that the causal factors for testicular cancer in Denmark are related to birth cohort and that non-seminoma and seminoma tumours have a common aetiology. An overall increase in testicular cancer incidence was found in the Nordic countries, corresponding to increases with each consecutive birth cohort in each country. In Denmark, a decline in incidence was observed during the past 5 years, and men born around 1943 and around 1968 showed lower incidences than men born just before or just after these dates. These birth-cohort effects were seen both for seminoma and non-seminoma tumours. This descriptive study confirms the hypothesis that birth cohort has a major influence on the incidence pattern of testicular tumours and suggests that seminoma and non-seminoma have common aetiological factors.

Cohort Studies↗

PubMed2005

Cancer incidence among Danish brewery workers.

Since the foundation of the Danish Brewery Workers' Union (BWU) in 1898, an integrated issue in the labour contract between the BWU and the employers implied that the breweries provided 6 bottles of beer to each brewery worker per day. The objective of our study is to investigate if this presumably high daily consumption of beer is associated with increased risk of cancer, particularly cancer of colon and rectum. The cohort has previously been followed until 1972, but with our study we add further 27 years of follow-up. The cohort comprises all male members of BWU employed for 6 months or longer in a brewery between 1939 and 1963. From the original cohort of 14,313 workers, it was possible to identify 13,051 brewery workers (91.2%). The identified brewery workers were linked to the Danish Cancer Registry for any cancer diagnoses during 1943-1999. The incidence rate of all Danish men was applied to calculate the expected number of cancers, standardised incidence ratios for age and time trend (O/E) were computed. A total of 3,928 cases of cancer were observed compared to 2,835.8 expected (O/E, 1.39; 95%-CI, 1.34-1.43). Significantly elevated risk of cancers was seen for cancer sites such as the buccal cavity, the digestive organs, the respiratory system and the urinary system. Members of the cohort were at a slightly but highly significant increased risk of both colon cancer (O/E, 1.26; 1.11-1.42) and rectum cancer (O/E, 1.31; 1.14-1.49). Our study shows that a high beer consumption is related to increased risk of several specific cancers, which supports that the relationship is of a causal nature.

Beer↗