Does Hair Dye Use Increase the Risk of Breast Cancer? A Population-Based Case-Control Study of Finnish Women

Introduction

Role of hair dyes in the etiology of breast cancer has occasionally raised concern but previous research has concluded with mixed results. Remnants of prohibited aromatic amines have been found in many hair dye products, and elevated levels of DNA-adducts of these amines have been detected from breast epithelial cells of hair dye users. However, the IARC working group has concluded that there is inadequate evidence for carcinogenicity of personal hair dye use and limited evidence in experimental animals for carcinogenicity of hair colorants.

Material and Methods

We investigated whether the use of hair dyes is associated with breast cancer risk in women. The study design was a retrospective population-based case-control study in Finland, with a self-administered questionnaire from 6,567 breast cancer patients, aged 22–60 years and diagnosed in 2000–2007, and their 21,598 matched controls. We report odds ratios (OR) with 95% confidence interval (95% CI) from a conditional logistic regression model applied to the frequency matched sets of cases and controls. Bias-adjusted odds ratios from the sensitivity analysis are also presented.

Results

After adjusting for potential confounders, the odds of breast cancer increased by 23% (OR: 1.23, 95% CI: 1.11–1.36) among women who used hair dyes compared to those who did not. In women born before 1950 an increase of 28% was noted (OR: 1.28, 95% CI: 1.10–1.48). We also observed a significant trend between the OR and cumulative use of hair dyes (P: 0.005). Bias-adjusted odds ratios varied between 1.04 and 2.50.

Conclusions

Our results suggest that use of hair dyes is associated with breast cancer incidence. The impact on public health may be substantial due to vast popularity of hair coloring in modern societies. It should be noted that regardless of all efforts, a possibility of bias cannot definitively be ruled out and use of a prospective design is warranted. Based on the present results, it may be concluded however that safety of hair dyes in relation to breast cancer cannot yet be fully acknowledged and lack of external safety assessment within the cosmetics industry is of major concern.     

High γ-Radiation Sensitivity Is Associated with Increased Gastric Cancer Risk in a Chinese Han Population: A Case-Control Analysis

Hypersensitivity to radiation exposure has been suggested to be a risk factor for the development of several malignancies, but not including gastric cancer. In this case-control study, radiation sensitivity as measured by chromatid breaks per cell (b/c) was examined in cultured peripheral blood lymphocytes (PBLs) from 517 patients with gastric cancer and 525 healthy controls. Our results showed that b/c values were significantly higher in cases than in controls (Mean [SD], 0.47 [0.20] vs. 0.34 [0.17]; P<0.001). Using the 50^th percentile value for controls (0.34 b/c) as the cutoff point, unconditional logistic regression analysis revealed that γ–radiation-sensitive individuals were at significantly higher risk for gastric cancer (adjusted odds ratio [OR] 2.01, 95% confidence interval [CI] 1.49–3.13). Quartile stratification analysis indicated a dose-response relationship between γ-radiation sensitivity and gastric cancer risk (P for trend <0.001). When using the subjects in first quartile of b/c values as reference, the adjusted ORs and corresponding CIs for the subjects in second, third, and fourth quartiles were 1.48 (0.91–2.17), 2.42 (1.76–3.64), and 3.40 (2.11–5.29), respectively. The γ-radiation sensitivity was related to age and smoking status. In addition, a clear joint effect on cancer risk was found between γ-Radiation sensitivity and smoking status. The risk for ever smokers with high sensitivity was higher than those for never smokers with high sensitivity and ever smokers with low sensitivity (OR [CI], 4.67 [2.31–6.07] vs. 2.14 [1.40–3.06] vs. 2.42 [1.57–3.95], respectively). No significant interaction was found between both factors (P for interaction  = 0.42). We conclude that chromatid radiosensitivity is associated with gastric cancer susceptibility in a Chinese population.     

Does Chronic Obstructive Pulmonary Disease with or without Type 2 Diabetes Mellitus Influence the Risk of Lung Cancer? Result from a Population-Based Cohort Study

Background

Previous studies have suggested that chronic obstructive pulmonary disease (COPD) is an independent risk factor for lung cancer. There are some evidence that people with diabetes are at a risk of developing many forms of cancer, but inconclusive with regard to lung cancer. The aim of this study was to evaluate whether COPD with or without type 2 diabetes mellitus (T2DM) influences the risk of developing lung cancer.

Methods

This is a retrospective cohort study consisting of 20,730 subjects newly diagnosed with COPD (“cases”). Their data was collected from the National Health Insurance system of Taiwan from 1998 to 2010. Among these patients, 5,820 patients had T2DM and 14,910 patients did not have T2DM. The retrospective matched control group consisted of 20,729 subjects without either COPD or T2DM. The control group was matched with the cases for sex, age, and index year (the year that the patient was diagnosed with COPD). The subjects were followed until the end of 2011.

Results

The findings of our study showed that the risk of lung cancer was higher in the COPD group than in the non-COPD group, with adjusted hazard ratio (HR) of 5.02 [95% confidence interval (CI) = 4.23–5.94] among total case group, adjusted HR was 5.38 (95% CI = 4.52–6.40) in the cohort without T2DM and adjusted HR was 4.05 (95% CI = 3.26–5.03) in the cohort with T2DM. We observed a significantly protective effect from lung cancer (adjusted HR = 0.75, 95% CI = 0.63–0.90) of diabetic cohort than non-diabetic cohort among patients with COPD.

Conclusion

Patients with COPD had a significantly higher risk of developing lung cancer than healthy people. However, there was a protective effect of T2DM for lung cancer among patients with COPD. Further investigation may be needed to corroborate the mechanism or bring up reliable reasons.     

Is Opium a Real Risk Factor for Esophageal Cancer or Just a Methodological Artifact? Hospital and Neighborhood Controls in Case-Control Studies

Background

Control selection is a major challenge in epidemiologic case-control studies. The aim of our study was to evaluate using hospital versus neighborhood control groups in studying risk factors of esophageal squamous cell carcinoma (ESCC).

Methodology/Principal Findings

We compared the results of two different case-control studies of ESCC conducted in the same region by a single research group. Case definition and enrollment were the same in the two studies, but control selection differed. In the first study, we selected two age- and sex-matched controls from inpatient subjects in hospitals, while for the second we selected two age- and sex-matched controls from each subject''s neighborhood of residence. We used the test of heterogeneity to compare the results of the two studies. We found no significant differences in exposure data for tobacco-related variables such as cigarette smoking, chewing Nass (a tobacco product) and hookah (water pipe) usage, but the frequency of opium usage was significantly different between hospital and neighborhood controls. Consequently, the inference drawn for the association between ESCC and tobacco use did not differ between the studies, but it did for opium use. In the study using neighborhood controls, opium use was associated with a significantly increased risk of ESCC (adjusted OR 1.77, 95% CI 1.17–2.68), while in the study using hospital controls, this was not the case (OR 1.09, 95% CI 0.63–1.87). Comparing the prevalence of opium consumption in the two control groups and a cohort enrolled from the same geographic area suggested that the neighborhood controls were more representative of the study base population for this exposure.

Conclusions/Significance

Hospital and neighborhood controls did not lead us to the same conclusion for a major hypothesized risk factor for ESCC in this population. Our results show that control group selection is critical in drawing appropriate conclusions in observational studies.     

Is the Transport of a Gadolinium-Based Contrast Agent Decreased in a Degenerated or Aged Disc? A Post Contrast MRI Study

A post contrast magnetic resonance imaging study has been performed in a wide population of low back pain patients to investigate which radiological and phenotypic characteristics influence the penetration of the contrast agent in lumbar discs in vivo. 37 patients affected by different pathologies (disc herniation, spondylolisthesis, foraminal stenosis, central canal stenosis) were enrolled in the study. The selected population included 26 male and 11 female subjects, with a mean age of 42.4±9.3 years (range 18–60). Magnetic resonance images of the lumbar spine were obtained with a 1.5 T scanner (Avanto, Siemens, Erlangen, Germany) with a phased-array back coil. A paramagnetic non–ionic contrast agent was injected with a dose of 0.4 ml/kg. T1-weighted magnetic resonance images were subsequently acquired at 5 time points, 5 and 10 minutes, 2, 4 and 6 hours after injection. Endplates presented clear enhancement already 5 minutes after injection, and showed an increase in the next 2 hours followed by a decrease. At 5 and 10 minutes, virtually no contrast medium was present inside the intervertebral disc; afterwards, enhancement significantly increased. Highly degenerated discs showed higher enhancement in comparison with low and medium degenerated discs. Discs classified as Pfirrmann 5 showed a statistically significant higher enhancement than Pfirrmann 1, 2 and 3 at all time points but the first one, possibly due to vascularization. Disc height collapse and Modic changes significantly increased enhancement. Presence of endplate defects did not show any significant influence on post contrast enhancement, but the lack of a clear classification of endplate defects as seen on magnetic resonance scans may be shadowing some effects. In conclusion, disc height, high level of degeneration and presence of Modic changes are factors which increase post contrast enhancement in the intervertebral disc. The effect of age could not be demonstrated.     

Is Zolpidem Associated with Increased Risk of Fractures in the Elderly with Sleep Disorders? A Nationwide Case Cross-Over Study in Taiwan

Background

We conducted a study using a case-crossover design to clarify the risk of acute effects of zolpidem and benzodiazepine on all-sites of fractures in the elderly.

Design of study

Case-crossover design.

Methods and Materials

Elderly enrollees (n = 6010) in Taiwan’s National Health Insurance Research Database with zolpidem or benzodiazepine use were analyzed for the risk of developing fractures.

Results

After adjusting for medications such as antipsychotics, antidepressants, and diuretics, or comorbidities such as hypertension, osteoarthritis, osteoporosis, rheumatoid arthritis and depression, neither zolpidem nor benzodiazepine was found to be associated with increased risk in all-sites fractures. Subjects without depression were found to have an increased risk of fractures. Diazepam is the only benzodiazepine with increased risk of fractures after adjusting for medications and comorbidities. Hip and spine were particular sites for increased fracture risk, but following adjustment for comorbidities, the associations were found to be insignificant.

Conclusion

Neither zolpidem nor benzodiazepine was associated with increased risk of all-site fractures in this case cross-over study after adjusting for medications or comorbidities in elderly individuals with insomnia. Clinicians should balance the benefits and risks for prescribing zolpidem or benzodiazepine in the elderly accordingly.     

Does Testosterone Therapy Increase the Risk of Prostate Cancer?

ObjectiveTo review factors affecting use of testosterone therapy for hypogonadism including the persistent controversial link between testosterone therapy and prostate cancer.MethodsWe reviewed studies investigating the relationship between testosterone therapy and prostate cancer progression and summarized strategies for hypogonadism management and prostate monitoring.ResultsTrials of up to 36 months in length and longitudinal studies consistently fail to demonstrate an increased prostate cancer risk associated with increased testosterone levels. No evidence of an associated relationship between exogenous testosterone therapy and prostate cancer has emerged from clinical trials or adverse event reports. It does not appear that exogenous testosterone accumulates in the prostate or provokes major biologic change in the prostate gland. In addition, preliminary evidence indicates that low endogenous testosterone may confer an increased risk of prostate cancer.ConclusionsMounting evidence demonstrates that there is a lack of association between testosterone therapy and prostate cancer progression. Testosterone therapy may be prescribed for men for whom it was once not considered. Careful monitoring of patients with hypogonadism who are receiving testosterone therapy is imperative. Well-designed, large-scale prospective clinical trials are necessary to adequately address prostate safety in hypogonadal men receiving testosterone therapy. (Endocr Pract. 2008;14:904-911)     

Bed-Sharing in the Absence of Hazardous Circumstances: Is There a Risk of Sudden Infant Death Syndrome? An Analysis from Two Case-Control Studies Conducted in the UK

Objective

The risk of sudden infant death syndrome (SIDS) among infants who co-sleep in the absence of hazardous circumstances is unclear and needs to be quantified.

Design

Combined individual-analysis of two population-based case-control studies of SIDS infants and controls comparable for age and time of last sleep.

Setting

Parents of 400 SIDS infants and 1386 controls provided information from five English health regions between 1993–6 (population: 17.7 million) and one of these regions between 2003–6 (population:4.9 million).

Results

Over a third of SIDS infants (36%) were found co-sleeping with an adult at the time of death compared to 15% of control infants after the reference sleep (multivariate OR = 3.9 [95% CI: 2.7–5.6]). The multivariable risk associated with co-sleeping on a sofa (OR = 18.3 [95% CI: 7.1–47.4]) or next to a parent who drank more than two units of alcohol (OR = 18.3 [95% CI: 7.7–43.5]) was very high and significant for infants of all ages. The risk associated with co-sleeping next to someone who smoked was significant for infants under 3 months old (OR = 8.9 [95% CI: 5.3–15.1]) but not for older infants (OR = 1.4 [95% CI: 0.7–2.8]). The multivariable risk associated with bed-sharing in the absence of these hazards was not significant overall (OR = 1.1 [95% CI: 0.6–2.0]), for infants less than 3 months old (OR = 1.6 [95% CI: 0.96–2.7]), and was in the direction of protection for older infants (OR = 0.1 [95% CI: 0.01–0.5]). Dummy use was associated with a lower risk of SIDS only among co-sleepers and prone sleeping was a higher risk only among infants sleeping alone.

Conclusion

These findings support a public health strategy that underlines specific hazardous co-sleeping environments parents should avoid. Sofa-sharing is not a safe alternative to bed-sharing and bed-sharing should be avoided if parents consume alcohol, smoke or take drugs or if the infant is pre-term.     

Type,Number or Both? A Population-Based Matched Case-Control Study on the Risk of Fall Injuries among Older People and Number of Medications beyond Fall-Inducing Drugs

Objectives

Drug use is a modifiable risk factor for fall-related injuries in older people. Whereas the injurious effect of polypharmacy is established, that of low numbers of medications has not been fully ascertained. Neither do we know whether it is the number per se or the type of medications that actually matters. We assessed this question for fall injuries leading to hospitalization.

Design

National register-based, population-based, matched case-control study.

Setting

Community dwellers aged 65+ years living in Sweden between March 2006 and December 2009.

Methods

Cases (n = 64,399) were identified in the national inpatient register and four controls per case were randomly matched by gender, date of birth and residential area. The association between number of prescribed medications, assessed through linkage with the Swedish prescribed drug register, and the risk of injurious falls was estimated with odds ratios with 95% confidence intervals using conditional logistic regression, adjusted for demographic and health status.

Results

The number of medications was associated with an increased risk of fall injury in a dose-response fashion, even after adjustment for marital status, comorbidity and number of fall-risk-inducing drugs (FRIDs). Using ten or more medications was associated with an almost two-fold higher risk (adjusted OR: 1.76, 95% CI: 1.66 to 1.88). When stratified by use (or not) of at least one FRID, the association weakened slightly among both non-users (adjusted OR: 1.50, 95% CI: 1.34 to 1.67) and users (adjusted OR: 1.67, 95% CI: 1.58 to 1.77).

Conclusion

In older people, not only large but also small numbers of medications may affect the risk for them to sustain injurious falls. Although the mechanisms lying behind this are complex, the finding challenges the prevention strategies targeting either specific types of medications (FRIDs) or high numbers of them.     

SORL1 Is Associated with the Risk of Late-Onset Alzheimer’s Disease: a Replication Study and Meta-Analyses

The sorting-related receptor gene (SORL1) has been defined as an interesting candidate gene for Alzheimer’s disease (AD). Recently, one novel variant, rs11218343, within SORL1 was reported to be related to late-onset Alzheimer’s disease (LOAD) in Caucasians, Korean, and Japanese. The aim of this case–control study is to investigate whether SORL1 rs11218343 contributes to susceptibility for LOAD in Chinese. Furthermore, our data, along with previously studies, were pooled for determining the risk of the rs11218343 polymorphism on LOAD. The rs11218343 polymorphism was genotyped in the 2350 independent subjects from Northern Han Chinese population (including 992 cases and 1358 age- and gender-matched controls). Result of the case–control study showed the association between rs11218343 polymorphism and the risk of LOAD in a Northern Han Chinese population (recessive model: odds ratio (OR)?=?0.641, 95 % confidence interval (CI)?=?0.464–0.884, P?=?0.007; additive model: OR?=?0.873, 95 % CI?=?0.765–0.996, P?=?0.043). The results of meta-analysis in subgroups (Caucasian and Asian) and the whole showed that the minor allele (C allele) within rs11218343 played a protective effect on AD risk (OR (95 % CI), 0.77 (0.72–0.83), 0.85 (0.79–0.91), 0.81 (0.76–0.85), respectively). In conclusion, the C allele in SORL1 rs11218343 may be a protective factor for LOAD in both Caucasian and Han Chinese.     

Visitors or Visits? An Examination of Zoo Visitor Numbers Using the Case Study of Australia

Usually cited in reference to the potential reach of zoo education, one of the popular figures for global zoo visitation is that 600 million people visit zoos annually. However, this number needs clarification on two fronts. First, there are many zoo visitors who are not included in the calculation because they visited a zoo that was not included in the count. Second, it does not take into consideration the people visit either the same or different zoos more than once annually. Using data collected from several sources, including zoo visitors themselves, this article focuses on one country—Australia—that contributes 15.6 million to the visitation total, and contends that the correct number of unique annual zoo visitors to Australian zoos is likely to be between 8 and 10 million. However, rather than suggesting an overemphasis on the potential of zoos for educating visitors, having regular repeat visitors represents a distinct advantage for zoos, allowing for progressive education opportunities. Zoo Biol. 32:37‐44, 2013. © 2012 Wiley Periodicals, Inc.     

An Ode to Joy … or the Sounds of Silence? An Exploration of Arts Education Policy in Australian Primary Schools

The arts are an integral and important component of our everyday lives. As such, they need to be a vital part of our children's education. However, this has rarely been the case in Australian state primary schools over the past two hundred years. This article explores the history of the arts in Australian state primary schools since the colonization of Australia to the present day. I examine how arts education has been subject to policy changes and inquiries that have not seemed to significantly benefit the arts in our schools and that have at times seemed to marginalize the arts in primary schools. The article concludes with a challenge to arts educators and other stakeholders to develop and implement a long-term approach to policy and practice to ensure that the arts serve as an “Ode to Joy” rather than dissolving into “Sounds of Silence.”     

Is a Cancer Diagnosis Associated with Subsequent Risk of Transient Global Amnesia?

Background

Psychological stress has been associated with transient global amnesia (TGA). Whether a cancer diagnosis, a severely stressful life event, is associated with subsequent risk of TGA has not been studied.

Methods

Based on the Swedish Cancer Register and Patient Register, we conducted a prospective cohort study including 5,365,608 Swedes at age 30 and above during 2001–2009 to examine the relative risk of TGA among cancer patients, as compared to cancer-free individuals. Incidence rate ratios (IRRs) and their 95% confidence intervals (CIs) derived from Poisson regression were used as estimates of the association between cancer diagnosis and the risk of TGA.

Results

During the study 322,558 individuals (6.01%) received a first diagnosis of cancer. We identified 210 cases of TGA among the cancer patients (incidence rate, 0.22 per 1000 person-years) and 4,887 TGA cases among the cancer-free individuals (incidence rate, 0.12 per 1000 person-years). Overall, after adjustment for age, sex, calendar year, socioeconomic status, education and civil status, cancer patients had no increased risk of TGA than the cancer-free individuals (IRR, 0.99; 95% CI, 0.86–1.13). The IRRs did not differ over time since cancer diagnosis or across individual cancer types. The null association was neither modified by sex, calendar period or age.

Conclusion

Our study did not provide support for the hypothesis that patients with a new diagnosis of cancer display a higher risk of TGA than cancer-free individuals.     

An epidemic of depression or the medicalization of distress?

The syndrome of major depression is widely regarded as a specific mental illness that has increased to the point where it will be second in the International Burden of Disease ranking by 2020. This article examines the assumption that major depression is a specific illness, that it is rapidly increasing, and that a medical response is justified. I argue that major depression is not a natural entity and does not identify a homogenous group of patients. The apparent increase in major depression results from: confusing those who are ill with those who share their symptoms; the surveying of symptoms out of context; the benefits that accrue from such a diagnosis to drug companies, researchers, and clinicians; and changing social constructions around sadness and distress. Standardized medical treatment of all these individuals is neither possible nor desirable. The major depression category should be replaced by a clinical staging strategy that acknowledges the continuous distribution of depressive symptoms. Trials that test social and lifestyle treatments as well as drugs and cognitive behavioral therapy across different levels of severity, chronicity, and symptom patterns might lead to the development of a coherent evidence-based stepped treatment model.     

Inhalation Toxicity of Humidifier Disinfectants as a Risk Factor of Children’s Interstitial Lung Disease in Korea: A Case-Control Study

Background

The occurrence of numerous cases of interstitial lung disease in children (chILD) every spring in Korea starting in 2006 raised suspicion about a causal relationship with the use of humidifier disinfectants (HDs). The aim of this study was to evaluate the association between HD use and the risk of chILD.

Methods

This retrospective, 1∶3 matched case-control study consisted of 16 cases of chILD that had developed between 2010 and 2011. The three groups of parallel controls (patients with acute lobar pneumonia, asthma, and healthy children) were matched by age, gender, and index date. Indoor/outdoor environmental risk factors, including HD use, were investigated by asking the guardians to complete a questionnaire.

Results

The median age of the affected children (43.8% male) was 26 months (18.25–36.25). The chILD group did not differ significantly from the control groups with respect to socio-demographic and clinical variables. Indoor and outdoor environmental factors were not associated with a risk of chILD. However, the previous use of HDs (OR; 2.73. 95% CI; 1.41–5.90, P = 0.00) were independently associated with an increased risk.

Conclusions

This study showed that HDs, which are widely used in South Korea in the winter season, independently increased the risk of chILD in spring. Therefore, continuous monitoring and, if needed, changes in policy are essential to prevent and control pediatric diseases caused by toxic chemicals.     

Is Ultrasound a Better Target than Clinical Disease Activity Scores in Rheumatoid Arthritis with Fibromyalgia? A Case-Control Study

Objectives

Our goal is to study the correlations among gray-scale seven-joint ultrasound score (GS-US7), power Doppler seven-joint ultrasound score (PD-US7), disease activity score-28 joints (DAS28), simplified disease activity index (SDAI) and clinical disease activity index (CDAI) in patients with and without fibromyalgia (FM).

Methods

A matched case-control study included all patients consecutively seen in the Rheumatoid Arthritis (RA) Clinic. Participants were allocated into one of two groups: RA with FM and RA without FM. Ultrasound (US) and clinical scoring were blinded for the presence of FM. Medians and proportions were compared by Mann-Whitney’s test and McNemar’s test, respectively. Spearman’s rank correlation coefficients (r_s) were calculated among clinical and US scores and differences were tested by r-to-z transformation test.

Results

Seventy-two women were included, out of 247 RA patients, mostly white, with median (IQR) age of 57.5 (49.3–66.8) years, with RA symptoms for 13.0 (6.0–19.0) years and FM symptoms for 6.0 (2.0–15.0) years. Disease-modifying antirheumatic drugs, non-steroidal anti-inflammatory drugs and prednisone use was comparable between groups. Objective activity parameters were not different between groups. RA patients with FM had greater DAS28, SDAI and CDAI but similar GS-US7 and PD-US7. GS-US7 correlated with DAS28, SDAI and CDAI in patients with and without FM (r_s = 0.36–0.57), while PD-US7 correlated with clinical scores only in patients without FM (r_s = 0.35–0.38).

Conclusion

To our knowledge, this is the first study to demonstrate that ultrasound synovitis scores are not affected by FM in RA patients. PD-US7 performed better than GS-US7 in long-standing RA patients with DAS28, SDAI or CDAI allegedly overestimated due to FM. Since sonographic synovitis predicts erosion better than swollen joint count, C-reactive protein and erythrocyte sedimentation rate, US should be considered a promising treatment target in RA patients with FM.