Indium lung—case reports and epidemiology

Purpose  

The present review is aimed to introduce an new occupational lung disease, Indium Lung.     

Leanness and lung cancer risk: fact or artifact?

BACKGROUND: More than a dozen studies have examined the association between leanness and increased lung cancer risk. None of the prospective studies has been large enough to allow exclusion of smokers or persons with preexisting disease, two factors that cause both leanness and poor survival and thus may cause a spurious association between low body mass index and fatal lung cancer. METHODS: Using Cox proportional hazards models, we examined this issue in a cohort of 941,105 U.S. adults enrolled in an American Cancer Society prospective study in 1982. During 14 years of follow-up, 14,066 people died of lung cancer. RESULTS: In analyses restricted to lifelong nonsmokers who did not report preexisting disease, leanness was not substantially associated with lung cancer mortality in men (rate ratio = 0.9; 95% confidence interval = 0.3-3.1) or in women (rate ratio = 1.2; 95% confidence interval = 0.7-2.1). However, leanness was associated with increased lung cancer risk in analyses that attempted to control for, rather than exclude, smokers and persons with preexisting disease. CONCLUSIONS: These data suggest that the association between leanness and lung cancer mortality is not causal but rather is an artifact of the effects of smoking and preexisting disease.     

Hormonal factors and risk of lung cancer among women?

BACKGROUND: Gender differences in the histological distribution of lung carcinoma and a possibly greater susceptibility of women than men to tobacco carcinogens, suggest a possible influence of sex-specific hormones. This study examines endocrine factors and risk of lung cancer among women by smoking status and histology. METHODS: We used data of a case-control study on lung cancer conducted from 1990 to 1996 in Germany, including 811 histologically confirmed female cases and 912 female population controls. Information on various menstrual and reproductive factors, use of oral contraceptives (OC), hormone replacement therapy (HRT), and smoking was gathered through personal interviews using a structured questionnaire. Odds ratios (OR) and 95% CI adjusted for age, region, smoking, and education were calculated via logistic regression. RESULTS: A reduction in lung cancer risk was observed with the use of OC (OR = 0.69; 95% CI: 0.51-0.92), but no trend in risk with increasing duration of use, age at first use, or calendar year of first use was present. A history of HRT was associated with a reduced risk (OR = 0.83; 95% CI: 0.64-1.09), particularly after long duration (>/=7 years) (OR = 0.59; 95% CI: 0.37-0.93). No clear association was found with regard to age at menarche, length of menstrual cycle, number of live-births, and age at menopause. Overall results did not differ much by histological cell subtype. The reduction in lung cancer risk associated with the use of exogenous hormones was primarily seen among smoking women. CONCLUSIONS: Our data provide evidence for a possible role of hormonal factors in the aetiology of lung cancer in women.     

Tea consumption and lung cancer risk: A meta-analysis of case–control and cohort studies

ObjectiveRecent epidemiologic studies, especially cohort and case–control studies, have yielded inconsistent findings regarding the association between tea consumption and risk for lung cancer. The aim of this study was to assess a potential relationship between tea consumption and the incidence of lung cancer worldwide.MethodsA systematic literature search of PubMed, Web of Science, the Cochrane Library, Google Scholar, the Chinese Biomedical Database, and Wanfang Database was conducted from 1966 to January 2014 by two investigators. All cohort studies and case–control studies that evaluated the association of tea and lung cancer were included. Summary relative risks (RR) and the corresponding 95% confidence intervals (CIs) were calculated using a random-effects model. Quality assessments were performed using the Newcastle–Ottawa Scale. Heterogeneity was assessed using the Q and I² tests, and the source of heterogeneity was detected by meta-regression analysis. Publication bias was evaluated with Egger's regression symmetry test. Subgroup analyses and sensitivity analysis were performed.ResultsThirty-eight lung cancer studies (26 case–control studies and 12 cohort studies) with 59,041 cases and 396,664 controls were included. Overall tea consumption was significantly associated with decreased risk for lung cancer (RR, 0.78; 95% CI, 0.70–0.87). Subgroup analyses showed that tea consumption was associated with reduced risk for lung cancer in women (RR, 0.76; 95% CI, 0.62–0.93), case–control studies (RR 0.72; 95% CI 0.63–0.83), Western studies (RR, 0.85; 95% CI, 0.75–0.97), and studies in China and Japan (RR, 0.74; 95% CI, 0.62–0.88). Both green tea (RR, 0.75; 95% CI, 0.62–0.91) and black tea (RR, 0.82; 95% CI, 0.71–0.94) were significantly associated with reduced lung cancer risk. No significant association was found in men or in cohort studies.ConclusionTea consumption may offer some protection against lung cancer.     

Vitamin A and female lung cancer: A case‐control study on plasma and diet

Plasma and dietary levels of retinol and β‐carotene were evaluated in a consecutive series of 47 females with histologically proven primary lung cancer and 159 nonneoplastic hospital controls. The dietary questionnaire included 69 different items: special care was given to foods rich in vitamin A and seasonal foods (e.g., vegetables and fruits), whereas serum analysis was focused on retinol and β‐carotene.

Age‐adjusted mean values for cases and controls were, respectively, 458.3 vs. 551.3 mg for plasma retinol, 276.1 vs. 390.1 mg for plasma carotene; 598.1 vs. 820.6 mg for daily retinol, and 628.0 vs. 882.5 mg for dietary carotene.

The odds ratios for low vs. high fertile, adjusted for age, smoking, retinol or carotene, cholesterol, and triglycerides by multivariate analysis were, respectively, 1.13 for plasma retinol, 5.04 for plasma carotene, 3.27 for dietary retinol, and 2.93 for dietary carotene. For all the ex‐amined items, there was a trend of increased risk for the second and third tertile, and statistical significance was reached for plasma β‐carotene (p < 0.05).

The hypothesis that a higher risk of lung cancer is related to a low vitamin A consumption is supported by these data.     

Does smoking influence the physical activity and lung cancer relation? A systematic review and meta-analysis

Research suggests an inverse association between physical activity and lung cancer. However, whether the relation is modified by degree of smoking adjustment has not been summarized. We conducted a meta-analysis of physical activity and lung cancer focusing on evaluating whether smoking status and the degree of smoking adjustment influenced the association. Comparing high versus low physical activity levels from 25 observational studies yielded a lung cancer summary relative risk (RR) of 0.79 [95 % confidence interval (CI) = 0.72–0.87], with RRs of 0.87 (95 % CI = 0.80–0.94) for cohort studies and 0.57 (95 % CI = 0.46–0.71) for case–control studies. In further analyses restricted to cohort studies, physical activity was inversely related to lung cancer among former smokers (RR = 0.68, 95 % CI = 0.51–0.90) and current smokers (RR = 0.80, 95 % CI = 0.70–0.90), whereas the association was null among never smokers (RR = 1.05, 95 % CI = 0.78–1.40, p interaction = 0.26). The degree of smoking adjustment did not modify the association (p interaction = 0.73). Physical activity was unrelated to lung cancer among never smokers but it was inversely associated with lung cancer among former and current smokers. Although the physical activity and lung cancer relation was not modified by smoking status or degree of smoking adjustment, residual confounding by smoking remains a possible explanation for the relations observed.     

What was the first epidemiological study of smoking and lung cancer?

Based on his critique of the early case-control study of smoking and lung cancer by Mueller, Morabia questions the priority that has been assigned to this research. I examine Morabia's approach to retrospectively assess quality and question its general applicability and replicability. By citation analyses, the case-control studies published in the 1950s have had far greater impact. Morabia's commentary points to the complexity and subtlety of re-interpreting older literature.     

A population-based case-control study on fruit and vegetable intake and lung cancer: a paradox effect?

A population-based case-control study was carried out in Northwest Spain to analyze the effect of fruit and vegetable intake on the appearance of lung cancer. A non-significant protective association was found for overall consumption of leafy green and other vegetables, with consumption once a day or more vs. less than once a week yielding odds ratios of 0.63 [95% confidence interval (CI) = 0.24-1.63] for leafy green vegetables and 0.64 (95% CI = 0.30-1.36) for other vegetables. A significant protective association was found for potato consumption. No protective associations were recorded for fruit, whether overall or singly; instead, fruit consumption once a day or more vs. less than once a week registered a risk of 2.16 (95% CI = 1.02-4.58). Although the possibility that this effect may be due to a phenomenon of reverse causation cannot be ruled out, these results could support other reports and hypotheses which indicate that the protective effect of fruit might not be as pronounced as generally thought.     

Dietary sugar and lung cancer: A case‐control study in Uruguay

To examine whether dietary sugar modifies lung cancer risk, a case‐control study involving 463 cases with lung cancer and 465 hospitalized controls was conducted in Uruguay in the period 1993–1996. Dietary patterns were assessed in detail using a 64‐item food‐frequency questionnaire, which allowed the calculation of total energy intake. After adjustment for potential confounders through a model that included tobacco smoking and total energy, total fat, vitamin C, and α‐carotene intakes, an increased risk for sugar‐rich foods, total sucrose intake, sucrose‐to‐dietary fiber ratio, and glycemic index for lung cancer was observed (odds ratio for highest category of total sucrose intake = 1.55, 95% confidence interval = 0.99–2.44). When lung cancer was analyzed separately by cell type, odds ratios for small cell and large cell undifferentiated carcinoma were higher than those observed for squamous cell and adenocarcinoma of the lung. The joint effect of pack‐years, total fat intake, and sucrose intake was associated with an increased risk of 28.3 (95% confidence interval = 13.4–59.7) for high values of the three variables. The study suggests that high sucrose intake could be an important risk factor in lung carcinogenesis. Further studies, both epidemiological and experimental, are needed to replicate the present findings and to clarify the mechanism(s) of sucrose intake in lung carcinogenesis.     

Differential patient–caregiver opinions of treatment and care for advanced lung cancer patients

This study examined the differences of opinion between cancer patients and caregivers with regard to treatment and care decisions. 184 advanced lung cancer patients and 171 primary caregivers were recruited as a convenience sample from hospitals in Cleveland, Ohio. A telephone interview was conducted to collect data using a semi-structured questionnaire. Nonparametric tests and regression analysis were performed. The findings showed that patients and caregivers reported significant disagreement on three main issues: trade-off between treatment side effects and benefits; reporting treatment side effects to physicians, and hospice care. Caregivers were more concerned about patient's quality of life and more willing to discuss hospice issues than were patients (p ≤ 01). Perceived family disagreement is associated with depression in both patients and caregivers (p ≤ 01; R²=8%). The study provided empirical evidence for patient–caregiver disagreement about treatment and care decisions and its significant adverse impact on both patients and caregivers.