Effectiveness of screening for colorectal cancer with a faecal occult-blood test, in Finland.

BACKGROUND: Screening for colorectal cancer (CRC) with guaiac-based faecal occult-blood test (FOBT) has been reported to reduce CRC mortality in randomised trials in the 1990s, but not in routine screening, so far. In Finland, a large randomised study on biennial FOB screening for CRC was gradually nested as part of the routine health services from 2004. We evaluate the effectiveness of screening as a public health policy in the largest population so far reported. METHODS: We randomly allocated (1:1) men and women aged 60-69 years to those invited for screening and those not invited (controls), between 2004 and 2012. This resulted in 180 210 subjects in the screening arm and 180 282 in the control arm. In 2012, the programme covered 43% of the target age population in Finland. RESULTS: The median follow-up time was 4.5 years (maximum 8.3 years), with a total of 1.6 million person-years. The CRC incidence rate ratio between the screening and control arm was 1.11 (95% CI 1.01 to 1.23). The mortality rate ratio from CRC between the screening and control arm was 1.04 (0.84 to 1.28), respectively. The CRC mortality risk ratio was 0.88 (0.66 to 1.16) and 1.33 (0.94 to 1.87) in males and females, respectively. CONCLUSIONS: We did not find any effect in a randomised health services study of FOBT screening on CRC mortality. The substantial effect difference between males and females is inconsistent with the evidence from randomised clinical trials and with the recommendations of several international organisations. Even if our findings are still inconclusive, they highlight the importance of randomised evaluation when new health policies are implemented. TRIAL REGISTRATION: 002_2010_august.

Effect of supervised and home exercise training on bone mineral density among breast cancer patients. A 12-month randomised controlled trial.

UNLABELLED: The ability of combined step aerobic- and circuit-training to prevent bone loss after breast cancer treatments was related to skeletal site and patients' menopausal status. Among premenopausal breast cancer survivors, a 12-month exercise intervention completely prevented bone loss at the femoral neck, whereas no exercise effect was seen at lumbar spine or at neither site in postmenopausal women. INTRODUCTION: The primary objective of this randomised clinical trial was to determine the preventive effect of supervised weight-bearing jumping exercises and circuit training on bone loss among breast cancer patients. METHODS: Of 573 breast cancer survivors aged 35-68 years randomly allocated into exercise or control group after adjuvant treatments, 498 (87%) were included in the final analysis. The 12-month exercise intervention comprised weekly supervised step aerobic- and circuit-exercises and similar home training. Bone mineral density (BMD) at lumbar spine and femoral neck were measured by dual-energy X-ray absorptiometry. Physical performance was assessed by 2-km walking and figure-8 running tests, and the amount of physical activity was estimated in metabolic equivalent-hours/week. RESULTS: In premenopausal women, bone loss at the femoral neck was prevented by exercise, the mean BMD changes being -0.2% among the trainees vs. -1.4% among the controls (p = 0.01). Lumbar bone loss could not be prevented (-1.9% vs. -2.2%). In postmenopausal women, no significant exercise-effect on BMD was found either at the lumbar spine (-1.6% vs. -2.1%) or femoral neck (-1.1% vs. -1.1%). CONCLUSIONS: This 12-month aerobic jumping and circuit training intervention completely prevented femoral neck bone loss in premenopausal breast cancer patients, whereas no effect on BMD was seen in postmenopausal women.

Education, survival and avoidable deaths in cancer patients in Finland.

BACKGROUND: Relative survival after cancer in Finland is at the highest level observed in Europe and has, in general, been on a steady increase. The aim of this study is to assess whether the high survival is equally shared by different population subgroups and to estimate the possible gains that might be achieved if equity prevailed. MATERIALS AND METHOD: The educational level and occupation before the cancer diagnosis of patients diagnosed in Finland in 1971-2005 was derived from an antecedent population census. The cancers were divided into 27 site categories. Cancer (cause)-specific 5-year survival proportions were calculated for three patient categories based on the educational level and for an occupational group of potentially health-conscious patients (physicians, nurses, teachers etc.). Proportions of avoidable deaths were derived by assuming that the patients from the two lower education categories would have the same mortality owing to cancer, as those from the highest educational category. Estimates were also made by additionally assuming that even the mortalities owing to other causes of death were all equal to those in the highest category. RESULTS: For almost all the sites considered, survival was consistently highest for patients with the highest education and lowest for those with only basic education. The potentially health-conscious patients had an even higher survival. The differences were, in part, attributable to less favourable distributions of tumour stages in the lower education categories. In 1996-2005, 4-7% of the deaths in Finnish cancer patients could have potentially been avoided during the first 5-year period after diagnosis, if all the patients had the same cancer mortality as the patients with the highest educational background. The proportion would have also been much higher, 8-11%, if, in addition, the mortality from other causes had been the same as that in the highest educational category. INTERPRETATION: Even in a potentially equitable society with high health care standards, marked inequalities persist in cancer survival. Earlier cancer diagnosis and the ability to cope within the health care system may be a partly relevant explanation, but personal habits and lifestyles also have a role, particularly for the cancer patients' mortality from other causes of death than cancer.

Effects of supplemental alpha-tocopherol and beta-carotene on colorectal cancer: results from a controlled trial (Finland)

BACKGROUND: Some epidemiological investigations suggest that higher intake or biochemical status of vitamin E and beta-carotene might be associated with reduced risk of colorectal cancer. METHODS: We tested the effects of alpha-tocopherol and beta-carotene supplementation on the incidence of colorectal cancer in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study, a double-blind, placebo-controlled trial among 29,133 50-69-year-old male cigarette smokers. Participants were randomly assigned to receive alpha-tocopherol (50 mg), beta-carotene (20 mg), both agents, or a placebo daily for 5-8 years. Incident colorectal cancers (n = 135) were identified through the nationwide cancer registry, and 99% were histologically confirmed. Intervention effects were evaluated using survival analysis and proportional hazards models. RESULTS: Colorectal cancer incidence was somewhat lower in the alpha-tocopherol arm compared to the no alpha-tocopherol arm, but this finding was not statistically significant (relative risk (RR) = 0.78, 95% confidence interval (CI) 0.55-1.09; log-rank test p = 0.15). Beta-carotene had no effect on colorectal cancer incidence (RR = 1.05, 95% CI 0.75-1.47; log-rank test p = 0.78). There was no interaction between the two substances. CONCLUSION: Our study found no evidence of a beneficial or harmful effect for beta-carotene in colorectal cancer in older male smokers, but does provide suggestive evidence that vitamin E supplementation may have had a modest preventive effect. The latter finding is in accord with previous research linking higher vitamin E status to reduced colorectal cancer risk.

CYP2D6 ultrarapid metabolizer genotype as a potential modifier of smoking behaviour.

Some 3-10% of Caucasians are deficient in CYP2D6 metabolism (poor metabolizers), due to inheritance of two defective alleles, whereas amplification of the CYP2D6 gene results in ultrarapid metabolism in 1-2% of Caucasian populations. To examine the possible association between CYP2D6 polymorphism and individual smoking behaviour, we analysed the prevalence of CYP2D6 genotypes among 292 long-term heavy smokers, 382 individuals with more variable smoking histories, and 302 never-smokers. The prevalence of ultrarapid metabolizers in heavy smokers (7.9%) was twofold compared to individuals with variable smoking habits (3.7%; odds ratio 2.3, 95% confidence interval 1.2-4.4), and fourfold compared with never-smokers (2.0%) (odds ratio 4.2, 95% confidence interval 1.8-9.8). The frequency of poor metabolizer genotype was approximately 2%, in each smoker group. However, when men and women were studied separately, the prevalence of poor metabolizer genotype was higher in male never-smokers (3.6%) than in variable smokers (2.7%) and heavy smokers (2.2%). Moreover, a trend test, adjusted by age, gender and cancer status, revealed a significant trend for the increased tobacco usage with increased metabolic capacity. Our results are in agreement with the assumption that increased CYP2D6 activity may contribute to the probability of being addicted to smoking.

Association between alcohol and lung cancer in the alpha-tocopherol, beta-carotene cancer prevention study in Finland.

OBJECTIVES: We evaluated the association between alcohol intake and lung cancer in a trial-based cohort in Finland, the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study (ATBC Study). METHODS: During an average of 7.7 years of follow-up, 1059 lung cancer cases were diagnosed among the 27,111 male smokers with complete alcohol and dietary information. The relationship between alcohol and lung cancer was assessed in multivariate Cox regression models that adjusted for age, smoking, body mass index and intervention group. RESULTS: Nondrinkers, 11% of the study population, were at increased lung cancer risk compared to drinkers (RR = 1.2, 95% CI: 1.0-1.4), possibly due to the inclusion of ex-drinkers who had stopped drinking for health reasons. Among drinkers only, we observed no association between lung cancer and total ethanol or specific beverage (beer, wine, spirits) intake. We found no significant effect modification by level of smoking, dietary micronutrients or trial intervention group; however, for men in the highest quartile of alcohol intake, we observed a slight increase in risk for lighter smokers (<1 pack/day) and reduced risk among the heaviest smokers (>30 cigarettes/day). CONCLUSIONS: We concluded that alcohol consumption was not a risk factor for lung cancer among male cigarette smokers, and its effect was not significantly modified by other factors, notably smoking history.

The effects of supplementation with alpha-tocopherol and beta-carotene on the incidence and mortality of carcinoma of the pancreas in a randomized, controlled trial.

BACKGROUND: Dietary components may be both causal and protective in cases of pancreatic carcinoma, but the preventive potential of single constituents has not been evaluated. The authors report the effects of alpha-tocopherol and beta-carotene supplementations on the rates of incidence of and mortality from pancreatic carcinoma in a randomized, controlled trial. METHODS: The 29,133 participants in the Alpha-Tocopherol Beta-Carotene Cancer Prevention (ATBC) Study were male smokers who were ages 50-69 years at the time they were randomized into 1 of the following 4 intervention groups: dl-alpha-tocopherol (AT; 50 mg/day), beta-carotene (BC; 20 mg/day), both AT and BC, and placebo. The daily supplementation lasted for 5-8 years. Incident cancers were identified through the national Finnish Cancer Registry and death certificates of the Statistics Finland. Results were analyzed by supplementation with Cox regression models. RESULTS: Effects of both supplementations were statistically nonsignificant. The rate of incidence of pancreatic carcinoma was 25% lower for the men who received beta-carotene supplements (n = 38) compared with the rate for those who did not receive beta-carotene (n = 51) (95% CI, -51% to 14%). Supplementation with alpha-tocopherol (n = 51) increased the rate of incidence by 34% (95% CI, -12% to 105%) compared with the rate for those who did not receive alpha-tocopherol. Mortality from pancreatic carcinoma during the follow-up, adjusted for stage and anatomic location of the tumor, was 19% (95% CI, -47% to 26%) lower among those who received beta-carotene and 11% (95% CI, -28% to 72%) higher among those who received alpha-tocopherol as compared with those who did not receive supplementation. CONCLUSIONS: Supplementation with beta-carotene or alpha-tocopherol does not have a statistically significant effect on the rate of incidence of pancreatic carcinoma or the rate of mortality caused by this disease.

Pancreatic cancer risk and nutrition-related methyl-group availability indicators in male smokers.

BACKGROUND: Few risk factors for pancreatic cancer have been identified, with age and cigarette smoking being the most consistent. The protective effect associated with consumption of fruits and vegetables-the major dietary sources of folate-is suggestive of a role for factors influencing cellular methylation reactions; however, to our knowledge, no study has investigated this relationship. Whether biochemical indicators of methyl-group availability are associated with exocrine pancreatic cancer risk was the focus of this investigation. METHODS: We conducted a nested case-control study within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study cohort of 29133 male Finnish smokers aged 50-69 years. One hundred twenty-six subjects with incident exocrine pancreatic cancer were matched by date of baseline blood draw (+/-30 days), study center, age (+/-5 years), trial intervention group, and completion of dietary history to 247 control subjects, who were alive and free from cancer at the time the case subjects were diagnosed. Odds ratios (ORs) and 95% confidence intervals (CIs) were determined by use of conditional logistic regression. Reported P values are two-tailed. RESULTS: Serum folate and pyridoxal-5'-phosphate (PLP) concentrations showed statistically significant inverse dose-response relationships with pancreatic cancer risk, with the highest serum tertiles having approximately half the risk of the lowest (folate: OR = 0.45; 95% CI = 0.24-0.82; P for trend = .009, and PLP: OR = 0.48; 95% CI = 0.26-0.88; P for trend = .02). An increased pancreatic cancer risk was also observed with greater exposure to cigarettes (e.g., pack-years [number of packs smoked per day x number of years of smoking], highest versus lowest quartile: OR = 2.13; 95% CI = 1.13-3.99; P for trend = .04). CONCLUSIONS: These results support the hypothesis that maintaining adequate folate and pyridoxine status may reduce the risk of pancreatic cancer and confirm the risk previously associated with cigarette smoking.

An international evaluation of the cancer preventive potential of vitamin A.

The IARC convened a Working Group of experts in May 1998 to evaluate the cancer preventive potential of vitamin A and to compile the third volume of the IARC Handbooks of Cancer Prevention. The handbook is intended to provide a comprehensive review of the relevant information in the published scientific literature through April 1998 on the role of vitamin A in cancer prevention. The focus of this critical review and commentary is on retinol and the retinyl esters. Much of the scientific literature in this field overlaps with studies involving vitamin A metabolites, vitamin A precursors, and studies of total dietary vitamin A (which is a combination of preformed vitamin A and its precursors), so work from this wide range of research is included in this review when it is deemed relevant to our understanding of the effects of retinol or retinyl esters on cancer development. The observed effects of preformed vitamin A on cell and organ culture, on animal models, in dietary observational epidemiological studies, and in human intervention studies was reviewed in the meeting. In summary, there is little evidence that vitamin A intake has any substantial cancer-preventive effects.

Incidence of cataract operations in Finnish male smokers unaffected by alpha tocopherol or beta carotene supplements.

OBJECTIVE: To examine the effect of alpha tocopherol and beta carotene supplementation on the incidence of age related cataract extraction. SETTING: The Alpha-tocopherol Beta-carotene (ATBC) Study was a randomised, double blind, placebo controlled, 2 x 2 factorial trial conducted in south western Finland. The cataract surgery study population of 28,934 male smokers 50-69 years of age at the start. INTERVENTION: Random assignment to one of four regimens: alpha tocopherol 50 mg per day, beta carotene 20 mg per day, both alpha tocopherol and beta carotene, or placebo. Follow up continued for five to eight years (median 5.7 years) with a total of 159,199 person years. OUTCOME MEASURE: Cataract extraction, ascertained from the National Hospital Discharge Registry. RESULTS: 425 men had cataract surgery because of senile or presenile cataract during the follow up. Of these, 112 men were in the alpha tocopherol alone group, 112 men in the beta carotene alone group, 96 men in the alpha tocopherol and beta carotene group, and 105 men in the placebo group. When supplementation with alpha tocopherol and with beta carotene were introduced to a Cox proportional hazards model with baseline characteristics (age, education, history of diabetes, body mass index, alcohol consumption, number of cigarettes smoked daily, smoking duration, visual acuity, and total cholesterol), neither alpha tocopherol (relative risk, RR, 0.91, 95% confidence intervals, CI, 0.74, 1.11) nor beta carotene (RR 0.97, 95% CI 0.79, 1.19) supplementation affected the incidence of cataract surgery. CONCLUSION: Supplementation with alpha tocopherol or beta carotene does not affect the incidence of cataract extractions among male smokers.

An international evaluation of the cancer preventive potential of carotenoids.

The IARC convened a Working Group of experts in December 1997 to evaluate the cancer-preventive potential of carotenoids and to compile the second volume of the IARC Handbooks of Cancer Prevention. In observational epidemiological studies, beta-carotene is associated with reduced risks for cancer at many but not all sites. It is unclear, however, to what extent beta-carotene itself is responsible for the decreased risks observed. Three large, randomized, placebo-controlled clinical trials indicate, however, that, in substantial doses, supplementation with beta-carotene not only does not prevent lung cancer but may actually increase the risk among individuals initially at high risk of lung cancer. These trials do not provide clear evidence concerning cancers at other specific sites. Thus, the Working Group considered that there is evidence suggesting a lack of cancer-preventive activity for beta-carotene when it is used as a supplement at high doses. At usual dietary levels of beta-carotene, the evidence for cancer-preventive activity was considered inadequate. However, there is sufficient evidence that beta-carotene has cancer-preventive activity in experimental animals, based on models of skin carcinogenesis in mice and buccal pouch carcinogenesis in hamsters. The observational epidemiological data on alpha-carotene, lycopene, and lutein are much less extensive than those for beta-carotene. For canthaxanthin, there are no published data regarding associations with cancer risk. These carotenoids have not been studied in human trials for cancer prevention. In animal models, there is sufficient evidence for canthaxanthin and limited evidence for alpha-carotene, lycopene, and lutein of cancer-preventive activity. Pending further research, supplemental beta-carotene, canthaxanthin, alpha-carotene, lutein, and lycopene should not be recommended for cancer prevention in the general population.

The association between baseline vitamin E, selenium, and prostate cancer in the alpha-tocopherol, beta-carotene cancer prevention study.

The association between prostate cancer and baseline vitamin E and selenium was evaluated in the trial-based cohort of the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study (n = 29,133). During up to 9 years of follow-up, 317 men developed incident prostate cancer. Multivariate Cox proportional hazards models that adjusted for intervention group, benign prostatic hyperplasia, age, smoking, and urban residence were used to evaluate associations between prostate cancer and exposures of interest. There were no significant associations between baseline serum alpha-tocopherol, dietary vitamin E, or selenium and prostate cancer overall. The associations between prostate cancer and vitamin E and some of the baseline dietary tocopherols differed significantly by alpha-tocopherol intervention status, with the suggestion of a protective effect for total vitamin E among those who received the alpha-tocopherol intervention (relative risk was 1.00, 0.68, 0.80, and 0.52 for increasing quartiles; P = 0.07).

Six-year supplementation with alpha-tocopherol and beta-carotene and age-related maculopathy.

PURPOSE: Animal research and observational studies in man suggest a protective effect of antioxidant vitamins in the development of age-related maculopathy (ARM). METHODS: The ATBC study, a population-based, controlled clinical trial of alpha-tocopherol and beta carotene to prevent lung cancer, took place in Finland between 1984 and 1993. Over 29,000 smoking males aged 50 to 69 years were randomly assigned to alpha-tocopherol (AT; 50 mg/day), beta-carotene (BC; 20 mg/day), both of these, or placebo. We performed an end-of-trial ophthalmological examination on a random sample of 941 participants aged 65 years or more from two of the fourteen study areas, to discover if the five to eight-year intervention with alpha-tocopherol and/or beta-carotene had been associated with a difference in ARM prevalence. Age-related maculopathy was assessed using colour photographs of the macula. RESULTS: Altogether, 269 cases of ARM were found; there were more cases in the AT group (32%; 75/237), BC group (29%; 68/234), and combined antioxidant group (28%; 73/257) than in the placebo group (25%; 53/213). However, neither substance was significantly associated with the risk of ARM in a logistic regression analysis controlling for possible risk factors. CONCLUSIONS: No beneficial effect of long-term supplementation with alpha-tocopherol or beta-carotene on the occurrence of ARM was detected among smoking males.

Prostate cancer and supplementation with alpha-tocopherol and beta-carotene: incidence and mortality in a controlled trial.

BACKGROUND: Epidemiologic studies have suggested that vitamin E and beta-carotene may each influence the development of prostate cancer. In the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study, a controlled trial, we studied the effect of alpha-tocopherol (a form of vitamin E) and beta-carotene supplementation, separately or together, on prostate cancer in male smokers. METHODS: A total of 29133 male smokers aged 50-69 years from southwestern Finland were randomly assigned to receive alpha-tocopherol (50 mg), beta-carotene (20 mg), both agents, or placebo daily for 5-8 years (median, 6.1 years). The supplementation effects were estimated by a proportional hazards model, and two-sided P values were calculated. RESULTS: We found 246 new cases of and 62 deaths from prostate cancer during the follow-up period. A 32% decrease (95% confidence interval [CI] = -47% to -12%) in the incidence of prostate cancer was observed among the subjects receiving alpha-tocopherol (n = 14564) compared with those not receiving it (n = 14569). The reduction was evident in clinical prostate cancer but not in latent cancer. Mortality from prostate cancer was 41% lower (95% CI = -65% to -1%) among men receiving alpha-tocopherol. Among subjects receiving beta-carotene (n = 14560), prostate cancer incidence was 23% higher (95% CI = -4%-59%) and mortality was 15% higher (95% CI = -30%-89%) compared with those not receiving it (n = 14573). Neither agent had any effect on the time interval between diagnosis and death. CONCLUSIONS: Long-term supplementation with alpha-tocopherol substantially reduced prostate cancer incidence and mortality in male smokers. Other controlled trials are required to confirm the findings.

Physical activity and prostate cancer in the Alpha-Tocopherol, Beta-Carotene (ATBC) Cancer Prevention Study (Finland).

The association between physical activity and prostate cancer was evaluated in the trial-based cohort of the Alpha-Tocopherol, Beta-Carotene (ATBC) Cancer Prevention Study (n = 29,133). During up to nine years of follow-up, 317 men developed incident prostate cancer. The relationship between occupational, leisure, and combined activity and prostate cancer was assessed in multivariate Cox regression models that adjusted for intervention group, benign prostatic hyperplasia, age, smoking, and urban residence. Compared with sedentary workers, relative risks (RR) and 95 percent confidence intervals (CI) for occupational walkers, walker/lifters, and heavy laborers were 0.6 (CI = 0.4-1.0), 0.8 (CI = 0.5-1.3), and 1.2 (CI = 0.7-2.0), respectively. Among working men, leisure activity (active cf sedentary) was associated inversely with risk (RR = 0.7, CI = 0.5-0.9). This inverse association for leisure activity was observed, with the exception of heavy laborers, for all occupational activity levels, and was strongest among walkers compared with men sedentary at work and leisure, and to a lesser degree among walker/lifters. These results are consistent with a protective effect of physical activity on prostate cancer.

The effect of alpha-tocopherol and beta-carotene supplementation on COPD symptoms.

The effects of alpha-tocopherol (50 mg/d) and beta-carotene (20 mg/d) supplementation on symptoms of chronic obstructive pulmonary disease were studied among the 29,133 participants of the Alpha-Tocopherol Beta-Carotene Cancer Prevention Study undertaken to investigate the effects of these two substances in the prevention of lung and other cancers. During the follow-up the supplementations did not affect the recurrence or incidence of chronic cough, phlegm, or dyspnea. The prevalence of chronic bronchitis and dyspnea at baseline was lower among those with high dietary intake of beta-carotene (OR = 0.78 and 0.67, respectively) or vitamin E (OR = 0.87 and 0.77) and high serum beta-carotene (OR = 0.59 and 0.62) and alpha-tocopherol (OR = 0.76 and 0.82). High intake and serum levels of retinol were associated with low prevalence of dyspnea (OR = 0.84 and 0.80, respectively) but not with chronic bronchitis. The results indicate no benefit from supplementation with alpha-tocopherol or beta-carotene on the symptoms of chronic obstructive pulmonary disorders but support the beneficial effect of dietary intake of fruits and vegetables rich in these compounds.

Effects of supplemental beta-carotene, cigarette smoking, and alcohol consumption on serum carotenoids in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study.

We determined whether serum carotenoid or retinol concentrations were altered by beta-carotene supplementation in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study and whether such effects were modified by alcohol consumption or cigarette use. Participants in this substudy were 491 randomly selected men aged 58-76 y from the metropolitan Helsinki study center [237 receiving supplemental beta-carotene (20 mg/d) and 254 not receiving such supplementation]. Dietary carotenoids, retinol, and alcohol, and serum beta-carotene, alpha-tocopherol, retinol, and cholesterol were assessed at baseline. After an average of 6.7 y of supplementation, serum was collected and carotenoid, retinol, and alpha-tocopherol concentrations were determined by HPLC. Serum carotenoid fractions were highly correlated with each other (P < or = 0.0001). Compared with the unsupplemented group, the beta-carotene group had significantly higher serum concentrations of beta-carotene (1483%), alpha-carotene (145%), and beta-cryptoxanthin (67%) (P < or = 0.0001). Retinol concentrations were 6% higher (P = 0.03) and lutein was 11% lower (P = 0.02) in the supplemented group. Serum lycopene, zeaxanthin, and alpha-tocopherol did not differ according to beta-carotene-supplementation status. Although these beta-carotene-group differences were not significantly altered by amount of alcohol consumption, higher consumption (> 12.9 g/d, median) was related to lower (10-38%) concentrations of carotenoids, particularly beta-carotene, alpha-carotene, and beta-cryptoxanthin, in both the supplemented and unsupplemented groups. Smoking status did not significantly influence the supplementation-related differences in serum carotenoid and retinol values but concentrations of carotenoids were generally highest in participants who quit smoking while in the study and lowest in current smokers of > or = 20 cigarettes/d. This study showed that serum concentrations of non-beta-carotene carotenoids are altered by long-term beta-carotene supplementation and confirms the adverse effects of alcohol and cigarette smoking on serum carotenoids.

Beta-carotene did not work: aftermath of the ATBC study.

The results of the ATBC study, the first large intervention trial of antioxidants, were intriguing. While the possibility that beta-carotene may in some circumstances enhance carcinogenesis has now been confirmed in another large trial, the mechanisms of action remain obscure.

Long-term supplementation with alpha-tocopherol and beta-carotene and age-related cataract.

PURPOSE: To study if long-term supplementation with alpha-tocopherol or beta-carotene is associated with cataract prevalence and severity. METHODS: An end-of-trial random sample of 1828 participants from the randomized, double-blind, placebo-controlled clinical trial the alpha-tocopherol, beta-carotene cancer prevention study. The alpha-tocopherol, beta-carotene cancer prevention study was originally designed to examine whether supplementation with alpha-tocopherol or beta-carotene would reduce the incidence of lung cancer in male smokers. The participants for this study lived in Helsinki City or Uusimaa province and were at entry to the alpha-tocopherol, beta-carotene cancer prevention study 50 to 69 years old and smoked at least 5 cigarettes per day. They received alpha-tocopherol 50 mg/day, beta-carotene 20 mg/day, a combination of the two, or placebo supplements for 5 to 8 years (median 6.6 years). Outcome measures were: cortical, nuclear, and posterior subcapsular cataract, differentiated and quantified with lens opacity classification system (LOCS II). Lens opacity meter provided a continuous measure of cataract density. RESULTS: Supplementation with alpha-tocopherol or beta-carotene was not associated with the end-of-trial prevalence of nuclear (odds ratio 1.1 and 1.2, respectively), cortical (odds ratio 1.0 and 1.3, respectively), or posterior subcapsular cataract (odds ratio 1.1 and 1.0, respectively) when adjusted for possible confounders in logistic model. Neither did the median lens opacity meter values differ between the supplementation groups, indicating no effect of alpha-tocopherol or beta-carotene on cataract severity. CONCLUSION: Supplementation with alpha-tocopherol or beta-carotene for 5 to 8 years does not influence the cataract prevalence among middle-aged, smoking men.

Alpha-Tocopherol and beta-carotene supplements and lung cancer incidence in the alpha-tocopherol, beta-carotene cancer prevention study: effects of base-line characteristics and study compliance.

BACKGROUND: Experimental and epidemiologic investigations suggest that alpha-tocopherol (the most prevalent chemical form of vitamin E found in vegetable oils, seeds, grains, nuts, and other foods) and beta-carotene (a plant pigment and major precursor of vitamin A found in many yellow, orange, and dark-green, leafy vegetables and some fruit) might reduce the risk of cancer, particularly lung cancer. The initial findings of the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study (ATBC Study) indicated, however, that lung cancer incidence was increased among participants who received beta-carotene as a supplement. Similar results were recently reported by the Beta-Carotene and Retinol Efficacy Trial (CARET), which tested a combination of beta-carotene and vitamin A. PURPOSE: We examined the effects of alpha-tocopherol and beta-carotene supplementation on the incidence of lung cancer across subgroups of participants in the ATBC Study defined by base-line characteristics (e.g., age, number of cigarettes smoked, dietary or serum vitamin status, and alcohol consumption), by study compliance, and in relation to clinical factors, such as disease stage and histologic type. Our primary purpose was to determine whether the pattern of intervention effects across subgroups could facilitate further interpretation of the main ATBC Study results and shed light on potential mechanisms of action and relevance to other populations. METHODS: A total of 29,133 men aged 50-69 years who smoked five or more cigarettes daily were randomly assigned to receive alpha-tocopherol (50 mg), beta-carotene (20 mg), alpha-tocopherol and beta-carotene, or a placebo daily for 5-8 years (median, 6.1 years). Data regarding smoking and other risk factors for lung cancer and dietary factors were obtained at study entry, along with measurements of serum levels of alpha-tocopherol and beta-carotene. Incident cases of lung cancer (n = 894) were identified through the Finnish Cancer Registry and death certificates. Each lung cancer diagnosis was independently confirmed, and histology or cytology was available for 94% of the cases. Intervention effects were evaluated by use of survival analysis and proportional hazards models. All P values were derived from two-sided statistical tests. RESULTS: No overall effect was observed for lung cancer from alpha-tocopherol supplementation (relative risk [RR] = 0.99; 95% confidence interval [CI] = 0.87-1.13; P = .86, logrank test). beta-Carotene supplementation was associated with increased lung cancer risk (RR = 1.16; 95% CI = 1.02-1.33; P = .02, logrank test). The beta-carotene effect appeared stronger, but not substantially different, in participants who smoked at least 20 cigarettes daily (RR = 1.25; 95% CI = 1.07-1.46) compared with those who smoked five to 19 cigarettes daily (RR = 0.97; 95% CI = 0.76-1.23) and in those with a higher alcohol intake (> or = 11 g of ethanol/day [just under one drink per day]; RR = 1.35; 95% CI = 1.01-1.81) compared with those with a lower intake (RR = 1.03; 95% CI = 0.85-1.24). CONCLUSIONS: Supplementation with alpha-tocopherol or beta-carotene does not prevent lung cancer in older men who smoke. beta-Carotene supplementation at pharmacologic levels may modestly increase lung cancer incidence in cigarette smokers, and this effect may be associated with heavier smoking and higher alcohol intake. IMPLICATIONS: While the most direct way to reduce lung cancer risk is not to smoke tobacco, smokers should avoid high-dose beta-carotene supplementation.