Cancer deaths and cases attributable to lifestyle factors and infections in China, 2013

Background

The burden of cancer in China is high, and it is expected to further increase. Information on cancers attributable to potentially modifiable risk factors is essential in planning preventive measures against cancer. We estimated the number and proportion of cancer deaths and cases attributable to ever-smoking, second-hand smoking, alcohol drinking, low fruit/vegetable intake, excess body weight, physical inactivity, and infections in China, using contemporary data from nationally representative surveys and cancer registries.

Methods

The number of cancer deaths and cases in 2013 were obtained from the National Central Cancer Registry of China and data on most exposures were obtained from the China National Nutrition and Health Survey 2002 or 2006 and Global Adult Tobacco Smoking 2010. We used a bootstrap simulation method to calculate the number and proportion of cancer deaths and cases attributable to risk factors and their corresponding 95% confidence intervals (CIs), allowing for uncertainty in data.

Results

Approximately 718 000 (95% CI 702 100-732 200) cancer deaths in men and 283 100 (278 800-288 800) cancer deaths in women were attributable to the studied risk factors, accounting for 52% of all cancer deaths in men and 35% in women. The numbers for incident cancer cases were 952 500 (95% CI 934 200-971 400) in men and 442 700 (437 200-447 900) in women, accounting for 47% of all incident cases in men and 28% in women. The greatest proportions of cancer deaths attributable to risk factors were for smoking (26%), HBV infection (12%), and low fruit/vegetable intake (7%) in men and HBV infection (7%), low fruit/vegetable intake (6%), and second-hand smoking (5%) in women.

Conclusions

Effective public health interventions to eliminate or reduce exposure from these risk factors, notably tobacco control and vaccinations against carcinogenic infections, can have considerable impact on reducing the cancer burden in China.

Comprehensive analysis of hormone and genetic variation in 36 genes related to steroid hormone metabolism in pre- and postmenopausal women from the breast and prostate cancer cohort consortium (BPC3)

CONTEXT

Sex steroids play a central role in breast cancer development.

OBJECTIVE

This study aimed to relate polymorphic variants in 36 candidate genes in the sex steroid pathway to serum concentrations of sex steroid hormones and SHBG.

DESIGN

Data on 700 genetic polymorphisms were combined with existing hormone assays and data on breast cancer incidence, within the European Prospective Investigation into Cancer and Nutrition (EPIC) and the Nurses' Health Study (NHS) cohorts; significant findings were reanalyzed in the Multiethnic Cohort (MEC).

SETTING AND PARTICIPANTS

We analyzed data from a pooled sample of 3852 pre- and postmenopausal Caucasian women from EPIC and NHS and 454 postmenopausal women from MEC.

MAIN OUTCOME MEASURES

Outcome measures were SHBG, testosterone, dehydroepiandrosterone (DHEAS), androstenedione, estrone (E1), and estradiol (E2) as well as breast cancer risk.

RESULTS

Globally significant associations were found among pre- and postmenopausal women combined between levels of SHBG and the SHBG gene and between DHEAS and the FSHR and AKR1C3 genes. Among postmenopausal women, serum E1 and E2 were significantly associated with the genes CYP19 and FSHR, and E1 was associated with ESR1. None of the variants related to serum hormone levels showed any significant association with breast cancer risk.

CONCLUSIONS

We confirmed associations between serum levels of SHBG and the SHBG gene and of E1 and E2 and the CYP19 and ESR1 genes. Novel associations were observed between FSHR and DHEAS, E1, and E2 and between AKR1C3 and DHEAS.

Prospective study of chemical exposures and amyotrophic lateral sclerosis

BACKGROUND

Although environmental toxins, including pesticides, are suspected of contributing to the risk of amyotrophic lateral sclerosis (ALS), no data exist from large prospective investigations. This study assessed the association between exposure to chemicals and risk of ALS in a prospective cohort study.

METHODS

The relation between self-report of regular exposure to 11 different chemical classes or x rays and ALS mortality among over 1 million participants in the American Cancer Society's Cancer Prevention Study II was prospectively assessed. Follow-up from 1989 through 2004 identified 617 deaths from ALS among men and 539 among women. Adjusted rate ratios (RR) were calculated using Cox proportional hazards.

RESULTS

The RR for ALS mortality among individuals exposed to pesticides/herbicides compared with that among unexposed individuals was 1.07 (95% CI 0.79 to 1.44), but somewhat higher after excluding those with missing duration of pesticides exposure (RR 1.44; 95% CI 0.89 to 2.31; p = 0.14). A non-significant increase in ALS mortality was found among individuals who reported exposure to formaldehyde (RR 1.34; 95% CI 0.93 to 1.92). Excluding those with a missing duration of formaldehyde exposure, the RR was 2.47 (95% CI 1.58 to 3.86), and there was a strongly significant dose-response relation with increasing years of exposure (p trend = 0.0004).

CONCLUSIONS

There was little evidence for any association between pesticides/herbicide exposure and ALS. In contrast, evidence was found, suggesting an increased risk of ALS with formaldehyde exposure. Because of the longitudinal design, this result is unlikely to be due to bias, but it should nevertheless be interpreted cautiously and needs to be verified independently.

Temporal relationship between cigarette smoking and risk of Parkinson disease

OBJECTIVE

To characterize further the relationship between smoking history and Parkinson disease (PD) risk by considering temporal and qualitative features of smoking exposure, including duration, average intensity, and recentness, as well as the relative importance of smoking during different periods of life.

METHODS

We prospectively assessed incident PD from 1992 to 2001 among 79,977 women and 63,348 men participating in the Cancer Prevention Study II Nutrition Cohort, according to their cigarette smoking status and lifetime smoking histories.

RESULTS

During follow-up, 413 participants had definite or probable PD confirmed by their treating neurologists or medical record review. Compared with never smokers, former smokers had a relative risk (RR) of 0.78 (95% CI 0.64 to 0.95) and current smokers had an RR of 0.27 (95% CI 0.13 to 0.56). On average, participants with more years smoked, more cigarettes per day, older age at quitting smoking, and fewer years since quitting smoking had lower PD risk. The relative risks and trends did not vary significantly by sex. The cumulative incidence of PD was lowest among participants who quit smoking at later ages. A 30% to 60% decreased risk of PD was apparent for smoking as early as 15 to 24 years before symptom onset, but not for smoking 25 or more years before onset.

CONCLUSIONS

The lower risk of Parkinson disease among current and former smokers varied with smoking duration, intensity, and recentness. The dependence of this association on the timing of smoking during life is consistent with a biologic effect.

Prospective study of occupation and amyotrophic lateral sclerosis mortality

Occupational exposures are suspected of contributing to the risk of amyotrophic lateral sclerosis (ALS), but results of epidemiologic studies have been inconsistent. The authors prospectively assessed the relation between occupation and ALS mortality among more than 1 million participants in the Cancer Prevention Study II of the American Cancer Society. Follow-up from 1989 through 2002 identified 507 ALS deaths among men and 430 among women. Adjusted rate ratios were calculated by using Mantel-Haenszel weights and Cox proportional hazards. Among men, elevated ALS mortality was found for programmers (rate ratio = 4.55, 95% confidence interval: 1.46, 14.2; p = 0.009) and laboratory technicians (rate ratio = 1.96, 95% confidence interval: 1.04, 3.66; p = 0.04). Occupations previously associated with increased risk of ALS for which no increased risk was found included farmers, electricians, and welders, although the numbers of electricians (eight ALS deaths) and welders (two ALS deaths) were small. Among women, only machine assemblers had significantly increased ALS mortality (rate ratio = 2.81, 95% confidence interval: 1.05, 7.53; p = 0.04). Results, which suggest that male programmers and laboratory technicians and female machine assemblers may be at increased risk of death from ALS, should be interpreted cautiously, however, because they are based on small numbers.

A candidate gene approach to searching for low-penetrance breast and prostate cancer genes

Most cases of breast and prostate cancer are not associated with mutations in known high-penetrance genes, indicating the involvement of multiple low-penetrance risk alleles. Studies that have attempted to identify these genes have met with limited success. The National Cancer Institute Breast and Prostate Cancer Cohort Consortium--a pooled analysis of multiple large cohort studies with a total of more than 5,000 cases of breast cancer and 8,000 cases of prostate cancer--was therefore initiated. The goal of this consortium is to characterize variations in approximately 50 genes that mediate two pathways that are associated with these cancers--the steroid-hormone metabolism pathway and the insulin-like growth factor signalling pathway--and to associate these variations with cancer risk.

Prospective study of military service and mortality from ALS

BACKGROUND

Two recent studies suggest that the risk of ALS is increased among Gulf War veterans. It is not known whether military service outside of the Gulf War is associated with increased risk of ALS.

METHODS

The authors prospectively assessed the relation between service in the military and ALS mortality among participants in the Cancer Prevention Study II cohort of the American Cancer Society, a cohort that includes over 500,000 men from the 50 states, Washington, DC, and Puerto Rico. Participant follow-up was conducted from 1989 through 1998 for ALS mortality. There were a total of 280 deaths from ALS among 126,414 men who did not serve in the military and 281,874 who did. Adjusted relative risks (RRs) were calculated using Mantel-Haenszel weights and Cox proportional hazards.

RESULTS

Men who served in the military had an increased death rate from ALS (RR = 1.53; 95% CI: 1.12 to 2.09; p = 0.007) compared with those who did not serve. The increase in ALS mortality was observed among men who served in the Army or National Guard (RR = 1.54), Navy (RR = 1.87), Air Force (RR = 1.54), and Coast Guard (RR = 2.24); no increase in risk was found in men who served in the Marine Corps, although there were only 13,670 men in this group. The risk of ALS among men who served was elevated in every 5-year birth cohort from 1915 through 1939.

CONCLUSIONS

Military personnel have an increased risk of ALS. This increase appeared to be largely independent of the branch of service and the time period served.

Prospective study of cigarette smoking and amyotrophic lateral sclerosis

Cigarette smoking has been proposed as a risk factor for amyotrophic lateral sclerosis (ALS), but because of the low incidence of ALS this association has been examined only with case-control methods. The authors prospectively assessed the relation between cigarette smoking and ALS mortality among participants in the Cancer Prevention Study II cohort of the American Cancer Society, a cohort of over 1 million people enrolled in 1982 who completed a lifestyle questionnaire including a detailed smoking history at baseline. Causes of deaths were ascertained through death certificates; ALS was not identified separately until 1989. From January 1, 1989, through 1998, 291 women and 330 men died from ALS. The relative risk of ALS among current smokers compared with never smokers was 1.67 (95% confidence interval: 1.24, 2.24; p = 0.002) in women and 0.69 (95% confidence interval: 0.49, 0.99; p = 0.04) in men. The difference in the relative risk estimates between the sexes was statistically significant (p < 0.0003). This large prospective study provides limited evidence that current cigarette smoking may be associated with increased death rates from ALS in women but not in men.

Multivitamin use and colon cancer mortality in the Cancer Prevention Study II cohort (United States)

OBJECTIVE

Multivitamins contain several nutrients, including folic acid, which are hypothesized to reduce colon cancer risk. Previous epidemiologic studies have suggested that effects of multivitamins containing substantial amounts of folic acid (introduced in 1973) may not be evident until 15 or more years since first use.

METHODS

We examined the association between daily multivitamin use and colon cancer mortality among 806,397 US men and women in the Cancer Prevention Study II cohort who completed a questionnaire at enrollment in 1982 and were followed for mortality through 1998.

RESULTS

After multivariate adjustment, multivitamin use at enrollment showed little association with colon cancer mortality. After 15 years since first use of a multivitamin potentially containing folic acid, we observed slightly decreased risk of colon cancer mortality (rate ratio (RR) = 0.89, 95% confidence interval (CI) 0.80-0.99). Consistent with previous reports, this association was stronger among participants consuming two or more alcoholic drinks per day (RR = 0.71, 95% CI 0.56-0.91).

CONCLUSION

Our results are consistent with a modest reduction in colon cancer mortality associated with use of folic acid-containing multivitamins among moderate to heavy alcohol users.

Alcohol consumption increases the risk of fatal breast cancer (United States)

OBJECTIVE

To investigate the hypothesis that alcohol consumption increases the risk of breast cancer mortality.

METHODS

We examined breast cancer mortality in relation to self-reported alcohol consumption in women from the American Cancer Society Cancer Prevention Study (CPS)-II. After 14 years of follow-up, 1,442 eligible breast cancer deaths were observed among 242,010 women. Cox proportional hazards models were constructed for total alcohol consumption and for beer, wine, and liquor separately.

RESULTS

Total alcohol consumption was associated with increased risk of fatal breast cancer among post- but not pre- or perimenopausal women. Even less than one drink/day was associated with up to a 30% increase in breast cancer mortality among postmenopausal women compared to non-drinkers (RR = 1.3, 95% CI: 1.1-1.6 for women drinking 0.26-<1 drink/day). When examined separately, consumption of beer, wine, and liquor each increased the risk of breast cancer among postmenopausal women. We found no evidence that alcohol consumption was more deleterious among women at high risk for breast cancer compared to average-risk women.

CONCLUSION

This study adds to the evidence that postmenopausal women can reduce their risk of breast cancer by avoiding or minimizing their use of alcohol.

A prospective study of diet and stomach cancer mortality in United States men and women

Frequent consumption of fruits, vegetables, and whole grains has been associated with a reduced risk of stomach cancer in the majority of case-control studies of these factors: however, prospective studies have been less consistent. We examined the association between selected major food groups (citrus fruits, vegetables, whole grains, and processed meats) and risk of fatal stomach cancer in the Cancer Prevention Study (CPS) II cohort of 1.2 million United States men and women. During 14 years of follow-up, we documented 439 stomach cancer deaths in women and 910 in men after exclusion of individuals with prevalent cancers, inadequate diet information, and recent weight loss at baseline in 1982. After controlling for other risk factors, none of the food groups examined were associated with risk of stomach cancer except for an unexpected increased risk with vegetable consumption in women [relative risk (RR) = 1.25; 95% confidence interval (CI), 0.99-1.58; highest versus lowest tertile, P = 0.06 for trend]. A high overall plant food intake (a sum of vegetables, citrus fruit, and whole grains) was associated with reduced risk in men (RR = 0.79; 95% CI, 0.67-0.93; highest versus lowest tertile, P = 0.003 for trend), but not in women (RR = 1.18; 95% CI, 0.93-1.50; P = 0.16 for trend). Of individual foods examined, liver consumption greater than twice/week was associated with an increased risk of fatal stomach cancer in women (RR = 1.96; 95% CI, 1.09-3.53) and men (RR = 1.63; 95% CI, 1.02-2.62) compared with nonconsumers. This study supports a modest role for plant foods in reducing the risk of fatal stomach cancer in men, but not in women.

Determinants of DNA yield and quality from buccal cell samples collected with mouthwash

Buccal cells are becoming an important source of genomic DNA in epidemiological studies, but little is known about the effect of different sampling conditions on DNA quality and yield. We used a mouthwash protocol to collect six daily buccal cell samples from 35 healthy volunteers. Twenty-four individuals (six men and 18 women) correctly completed the protocol and were included in paired analyses to determine whether "swish" time (30 s versus 60 s), toothbrushing before collection, or lag time between collection and DNA extraction (1 day versus 5, 10, or 30 days at room temperature) would affect sample quality and yield. Total DNA, human-specific DNA (hDNA), degradation of DNA, and ability to amplify by PCR were determined. hDNA yield did not significantly vary by "swish" time. However, toothbrushing 1 h before sample collection reduced the amount of hDNA by nearly 40% (34 microg versus 21 microg; P = 0.06). Median hDNA yields for samples that were held for 1, 5, 10, and 30 days before extraction were 32 microg (range, 4-196), 32 microg (2-194), 23 microg (3-80), and 21 microg (5-56), respectively. The 10- and 30-day samples had significantly less hDNA than those processed after 1 day (P = 0.01). PCR success rates for beta-globin gene fragments of length 268 bp, 536 bp, and 989 bp were 94% or better, and high molecular weight DNA (>23 kb) was found in all but one sample. These results suggest that buccal cells should be collected before brushing teeth and processed within 5 days of collection to maximize hDNA yield.

Sun exposure and sun-protection behaviors and attitudes among U.S. youth, 11 to 18 years of age

BACKGROUND

Adolescence is a high-risk period for the development of melanoma and nonmelanocytic skin cancers later in life. This study examines the prevalence and correlates of sun-protection practices among U.S. youth.

METHODS

During July-October, 1998, a national, population-based telephone survey was conducted (N = 1,192 paired interviews of youth and their parents). Weighted prevalence and adjusted prevalence odds ratios and 95% confidence intervals were estimated. Multiple logistic regression analyses examined associations between sociodemographics, attitudes, and other modifiable correlates to specific behaviors.

RESULTS

Routinely practiced sun-protection behaviors among youth on sunny days were wearing sunglasses (32%) or long pants (21%), staying in the shade (22%), and applying sunscreen (31%). Fifty-eight percent used a sunscreen with SPF > or =15 when at the beach or pool. Age, sex, and sun sensitivity were associated with substantial variation in some sun-protection behaviors. Factors associated with specific sun-protection behaviors included a lower appeal to tanning, a higher perceived benefit of sun protection, and information from family and friends about sun protection.

CONCLUSION

Effective sun protection is practiced by less than one-third of U.S. youth. This baseline survey will help to monitor progress in skin cancer prevention in this critical age group in the future.

Arsenic

The toxicity and carcinogenicity of arsenic are well known, but vexing questions remain. The current controversy over the appropriate Federal limit for arsenic in drinking water highlights some of the difficult scientific, ethical, economic, and political issues that complicate standard-setting in occupational and environmental health. These include limitations in the scientific evidence concerning the risk at low doses, uncertainty about the appropriate mathematical models for estimating the risk at low-level exposures based on data from higher-level exposures, and controversies concerning the appropriate safety margin, level of evidence required for standard-setting, and costs of remediation.

Annual report to the nation on the status of cancer (1973 through 1998), featuring cancers with recent increasing trends

BACKGROUND

The American Cancer Society, the National Cancer Institute (NCI), the North American Association of Central Cancer Registries, and the Centers for Disease Control and Prevention, including the National Center for Health Statistics (NCHS), collaborate to provide an annual update on cancer occurrence and trends in the United States. This year's report contains a special feature that focuses on cancers with recent increasing trends.

METHODS

From 1992 through 1998, age-adjusted rates and annual percent changes are calculated for cancer incidence and underlying cause of death with the use of NCI incidence and NCHS mortality data. Joinpoint analysis, a model of joined line segments, is used to examine long-term trends for the four most common cancers and for those cancers with recent increasing trends in incidence or mortality. Statistically significant findings are based on a P value of.05 by use of a two-sided test. State-specific incidence and death rates for 1994 through 1998 are reported for major cancers.

RESULTS

From 1992 through 1998, total cancer death rates declined in males and females, while cancer incidence rates declined only in males. Incidence rates in females increased slightly, largely because of breast cancer increases that occurred in some older age groups, possibly as a result of increased early detection. Female lung cancer mortality, a major cause of death in women, continued to increase but more slowly than in earlier years. In addition, the incidence or mortality rate increased in 10 other sites, accounting for about 13% of total cancer incidence and mortality in the United States.

CONCLUSIONS

Overall cancer incidence and death rates continued to decline in the United States. Future progress will require sustained improvements in cancer prevention, screening, and treatment.

Vitamin supplement use and fatal non-Hodgkin's lymphoma among US men and women

The authors evaluated the association between use of individual supplements of vitamins A, C, and E only and multivitamins and fatal non-Hodgkin's lymphoma in a large prospective mortality study of US men and women. During 14 years of follow-up (1982-1996), 1,571 non-Hodgkin's lymphoma deaths among 508,351 men and 1,398 non-Hodgkin's lymphoma deaths among 676,306 women were documented. Long-term regular use of individual supplements of vitamins A, C, and E only and multivitamins was unrelated to fatal non-Hodgkin's lymphoma among either men or women. The multivariate relative risks for men who used supplements for 10 or more years were 1.03 (95% confidence interval (CI): 0.54, 2.00) for vitamin A supplements, 1.04 (95% CI: 0.78, 1.39) for vitamin C supplements, 1.06 (95% CI: 0.74, 1.51) for vitamin E supplements, and 1.14 (95% CI: 0.92, 1.40) for multivitamins. The multivariate relative risks for women who used supplements for 10 or more years were 1.40 (95% CI: 0.77, 2.54) for vitamin A supplements, 1.19 (95% CI: 0.89, 1.60) for vitamin C supplements, 1.27 (95% CI: 0.87, 1.84) for vitamin E supplements, and 1.21 (95% CI: 0.98, 1.50) for multivitamins. All associations became weaker when vitamin supplements were mutually adjusted. These findings do not support an important relation between long-term regular use of individual supplements of vitamins A, C, and E only and multivitamins and fatal non-Hodgkin's lymphoma.

Body mass index, height, and prostate cancer mortality in two large cohorts of adult men in the United States

Body weight and height have both been associated consistently with postmenopausal breast cancer but less consistently with prostate cancer. The present study examined the relationship between body mass index (BMI), height, and death from prostate cancer in two large American Cancer Society cohorts. Men in the study were selected from the male participants in Cancer Prevention Study I (CPS-I; enrolled in 1959 and followed through 1972) and Cancer Prevention Study II (CPS-II; enrolled in 1982 and followed through 1996). After exclusions, 1,590 prostate cancer deaths remained among 381,638 men in CPS-I and 3,622 deaths among 434,630 men in CPS-II. Cox proportional hazards modeling was used to compute rate ratios (RR) and to adjust for confounders. Prostate cancer mortality rates were significantly higher among obese (BMI, > or =30) than nonobese (BMI, <25) men in both cohorts [adjusted RR, 1.27; 95% confidence interval (CI), 1.04-1.56 in CPS-I; RR, 1.21; 95% CI, 1.07-1.37 in CPS-II]. Prostate cancer mortality rates in the CPS-I cohort were lowest for the shortest men (RR, 0.80; 95% CI, 0.63-1.03 for men <65 inches versus 65-66 inches) and highest for the tallest men (RR, 1.39; 95% CI, 1.11-1.74 for men > or =73 inches tall versus 65-66 inches). Rates remained constant among men 65-72 inches tall. No association between height and prostate cancer mortality was observed in the CPS-II cohort (RR, 1.03; 95% CI, 0.82-1.29 for men > or =75 versus 65-66 inches). These results support the hypothesis that obesity increases risk of prostate cancer mortality. Decreased survival among obese men may be a likely explanation for this association.

Estrogen replacement therapy and ovarian cancer mortality in a large prospective study of US women

CONTEXT

Postmenopausal estrogen use is associated with increased risk of endometrial and breast cancer, 2 hormone-related cancers. The effect of postmenopausal estrogen use on ovarian cancer is not established.

OBJECTIVES

To examine the association between postmenopausal estrogen use and ovarian cancer mortality and to determine whether the association differs according to duration and recency of use.

DESIGN AND SETTING

The American Cancer Society's Cancer Prevention Study II, a prospective US cohort study with mortality follow-up from 1982 to 1996.

PARTICIPANTS

A total of 211 581 postmenopausal women who completed a baseline questionnaire in 1982 and had no history of cancer, hysterectomy, or ovarian surgery at enrollment.

MAIN OUTCOME MEASURE

Ovarian cancer mortality, compared among never users, users at baseline, and former users as well as by total years of use of estrogen replacement therapy (ERT).

RESULTS

A total of 944 ovarian cancer deaths were recorded in 14 years of follow-up. Women who were using ERT at baseline had higher death rates from ovarian cancer than never users (rate ratio [RR], 1.51; 95% confidence interval [CI], 1.16-1.96). Risk was slightly but not significantly increased among former estrogen users (RR, 1.16; 95% CI, 0.99-1.37). Duration of use was associated with increased risk in both baseline and former users. Baseline users with 10 or more years of use had an RR of 2.20 (95% CI, 1.53-3.17), while former users with 10 or more years of use had an RR of 1.59 (95% CI, 1.13-2.25). Annual age-adjusted ovarian cancer death rates per 100 000 women were 64.4 for baseline users with 10 or more years of use, 38.3 for former users with 10 or more years of use, and 26.4 for never users. Among former users with 10 or more years of use, risk decreased with time since last use reported at study entry (RR for last use <15 years ago, 2.05; 95% CI, 1.29-3.25; RR for last use >/=15 years ago, 1.31; 95% CI, 0.79-2.17).

CONCLUSIONS

In this population, postmenopausal estrogen use for 10 or more years was associated with increased risk of ovarian cancer mortality that persisted up to 29 years after cessation of use.

Cellular phones and risk of brain tumors

As cellular telephones are a relatively new technology, we do not yet have long-term follow-up on their possible biological effects. However, the lack of ionizing radiation and the low energy level emitted from cell phones and absorbed by human tissues make it unlikely that these devices cause cancer. Moreover, several well-designed epidemiologic studies find no consistent association between cell phone use and brain cancer. It is impossible to prove that any product or exposure is absolutely safe, especially in the absence of very long-term follow-up. Accordingly, the following summary from the Food and Drug Administration Center for Devices and Radiological Health offers advice to people concerned about their risk: If there is a risk from these products--and at this point we do not know that there is--it is probably very small. But if people are concerned about avoiding even potential risks, there are simple steps they can take to do so. People who must conduct extended conversations in their cars every day could switch to a type of mobile phone that places more distance between their bodies and the source of the RF, since the exposure level drops off dramatically with distance. For example, they could switch to: a mobile phone in which the antenna is located outside the vehicle, a hand-held phone with a built-in antenna connected to a different antenna mounted on the outside of the car or built into a separate package, or a headset with a remote antenna to a mobile phone carried at the waist. Again the scientific data do not demonstrate that mobile phones are harmful. But if people are concerned about the radiofrequency energy from these products, taking the simple precautions outlined above can reduce any possible risk. In addition, people who are concerned might choose digital rather than analog telephones, since the former use lower RF levels.

Tubal sterilization and risk of breast cancer mortality in US women

OBJECTIVE

To investigate the hypothesis that tubal sterilization is associated with a reduced risk of breast cancer.

METHODS

We examined this hypothesis in a large prospective study of US adults. After 14 years of mortality follow-up, 3837 deaths from breast cancer were observed in a cohort of 619,199 women who were cancer-free at study entry in 1982.

RESULTS

Cox proportional hazards models (adjusted for multiple breast cancer risk factors) showed a significant inverse association between tubal sterilization and breast cancer mortality (adjusted rate ratio (RR) = 0.82, 95% confidence interval (CI) 0.70-0.96). Women who were sterilized before age 35 had a lower risk (adjusted RR = 0.69, 95% CI 0.53-0.88) than women who were sterilized at 35 years of age or older (adjusted RR = 0.92, 95% CI 0.75-1.13). Also, sterilizations performed before 1975 resulted in a lower risk (RR = 0.75, 95% CI 0.62-0.91) than those performed during or after 1975 (RR = 0.98, 95% CI 0.74-1.29), possibly reflecting the likelihood of greater tissue damage with earlier procedures.

CONCLUSIONS

These results suggest that tubal sterilization may lower subsequent risk of breast cancer, especially among women who are sterilized at a relatively young age. Additional studies are needed to confirm or refute these findings.

Effect of body mass on the association between estrogen replacement therapy and mortality among elderly US women

In observational studies, estrogen replacement therapy is associated with decreased cardiovascular disease rates and increased breast cancer rates. Recent evidence suggests that the impact of estrogen use on disease outcomes may vary by body mass. In a prospective study of 290,827 postmenopausal US women with no history of cancer or cardiovascular disease at enrollment in 1982, the authors examined the association between postmenopausal estrogen use and all-cause, coronary heart disease, stroke, all-cancer, and breast cancer death rates and whether these associations differed by body mass. After 12 years of follow-up, results from Cox proportional hazards models showed that all-cause death rates were lower among baseline estrogen users than never users (rate ratio (RR) = 0.82, 95% confidence interval (CI): 0.78, 0.87). The lowest relative risk was found for coronary heart disease (RR = 0.66, 95% CI: 0.58, 0.77). The inverse association between estrogen use and coronary heart disease mortality was strongest for thin women (body mass index <22 kg/m2) (RR = 0.49, p for interaction = 0.02). Breast cancer mortality did not increase with estrogen use overall, and no increased risk was observed for thin or heavy women. In this population, the reduction in coronary heart disease mortality among estrogen users was greatest for thinner women. Additional studies are needed to confirm or refute these results.

Vitamin C and vitamin E supplement use and colorectal cancer mortality in a large American Cancer Society cohort

Some recent epidemiological studies have suggested that use of vitamin C or vitamin E supplements, both of which are important antioxidants, may substantially reduce the risk of colon or colorectal cancer. We examined the association between colorectal cancer mortality and use of individual vitamin C and E supplements in the American Cancer Society's Cancer Prevention Study II cohort. We used proportional hazards modeling to estimate rate ratios among 711,891 men and women in the United States who completed a self-administered questionnaire at study enrollment in 1982, had no history of cancer, and were followed for mortality through 1996. During the 14 years of follow-up, 4404 deaths from colorectal cancer occurred. After adjustment for multiple colorectal cancer risk factors, regular use of vitamin C or E supplements, even long-term use, was not associated with colorectal cancer mortality. The combined-sex rate ratios were 0.89 [95% confidence interval (CI), 0.73-1.09] for 10 or more years of vitamin C use and 1.08 (95% CI, 0.85-1.38) for 10 or more years of vitamin E use. In subgroup analyses, use of vitamin C supplements for 10 or more years was associated with decreased risk of colorectal cancer mortality before age 65 years (rate ratio = 0.48; 95% CI, 0.28-0.81) and decreased risk of rectal cancer mortality at any age (rate ratio = 0.40; 95% CI, 0.20-0.80). Our results do not support a substantial effect of vitamin C or E supplement use on overall colorectal cancer mortality.

Health impact of "reduced yield" cigarettes: a critical assessment of the epidemiological evidence

Cigarettes with lower machine measured "tar" and nicotine yields have been marketed as "safer" than high tar products over the last four decades, but there is conflicting evidence about the impact of these products on the disease burden caused by smoking. This paper critically examines the epidemiological evidence relevant to the health consequences of "reduced yield" cigarettes. Some epidemiological studies have found attenuated risk of lung cancer but not other diseases, among people who smoke "reduced yield" cigarettes compared to smokers of unfiltered, high yield products. These studies probably overestimate the magnitude of any association with lung cancer by over adjusting for the number of cigarettes smoked per day (one aspect of compensatory smoking), and by not fully considering other differences between smokers of "high yield" and "low yield" cigarettes. Selected cohort studies in the USA and UK show that lung cancer risk continued to increase among older smokers from the 1950s to the 1980s, despite the widespread adoption of lower yield cigarettes. The change to filter tip products did not prevent a progressive increase in lung cancer risk among male smokers who began smoking during and after the second world war compared to the first world war era smokers. National trends in vital statistics data show declining lung cancer death rates in young adults, especially males, in many countries, but the extent to which this is attributable to "reduced yield" cigarettes remains unclear. No studies have adequately assessed whether health claims used to market "reduced yield" cigarettes delay cessation among smokers who might otherwise quit, or increase initiation among non-smokers. There is no convincing evidence that past changes in cigarette design have resulted in an important health benefit to either smokers or the whole population. Tobacco control policies should not allow changes in cigarette design to subvert or distract from interventions proven to reduce the prevalence, intensity, and duration of smoking.

Cigarette smoking and colorectal cancer mortality in the cancer prevention study II

BACKGROUND

Recent studies suggest that long-term cigarette smoking is associated with an increased risk of colorectal cancer. Whether the association is causal or due to confounding remains unclear.

METHODS

We examined cigarette smoking in relation to colorectal cancer mortality, evaluating smoking duration and recency and controlling for potential confounders in the Cancer Prevention Study II. This prospective nationwide mortality study of 1 184 657 adults (age > or =30 years) was begun by the American Cancer Society in 1982. After exclusions, our analytic cohort included 312 332 men and 469 019 women, among whom 4432 colon or rectal cancer deaths occurred between 1982 and 1996 among individuals who were cancer free in 1982. Rate ratios (RRs) and 95% confidence intervals (CIs) were estimated by fitting Cox proportional hazards models. All statistical tests were two-sided.

RESULTS

Multivariate-adjusted colorectal cancer mortality rates were highest among current smokers, were intermediate among former smokers, and were lowest in lifelong nonsmokers. The multivariate-adjusted RR (95% CI) for current compared with never smokers was 1.32 (1.16-1.49) among men and 1.41 (1.26-1.58) among women. Increased risk was evident after 20 or more years of smoking for men and women combined as compared with never smokers. Risk among current and former smokers increased with duration of smoking and average number of cigarettes smoked per day; risk in former smokers decreased significantly with years since quitting. If the multivariate-adjusted RR estimates in this study do, in fact, reflect causality, then approximately 12% of colorectal cancer deaths among both men and women in the general U.S. population in 1997 were attributable to smoking.

CONCLUSIONS

Long-term cigarette smoking is associated with increased risk of colorectal cancer mortality in both men and women. Clear reduction in risk is observed with early smoking cessation.

Predictors of pancreatic cancer mortality among a large cohort of United States adults

OBJECTIVES

Cigarette smoking is considered an important risk factor for pancreatic cancer, but other purported risk factors are less well established. To learn more about the epidemiology of this important cause of mortality we examined associations with a variety of possible risk factors for death from pancreatic cancer in a large, prospective study of United States adults.

METHODS

We used proportional hazards models to obtain adjusted estimates of relative risks (hazards ratios). During 14 years of follow-up, 3751 persons died of pancreatic cancer in a cohort of 483,109 men and 619,199 women who had no reported history of cancer at enrollment in 1982.

RESULTS

Cigarette smoking at baseline was associated with fatal pancreatic cancer among men (multivariate relative risk [RR] = 2.1, 95% confidence interval [CI] 1.9-2.4) and among women (RR = 2.0, 95% CI 1.8-2.3). A trend in risk was observed with increasing number of cigarettes smoked per day among current smokers at baseline. With several variables included in separate models for men and women, we found additional factors to be predictive of pancreatic cancer mortality, including family history of pancreatic cancer, black race, diabetes, and increased body mass index. History of gallstones was predictive of pancreatic cancer among men. An inverse association with vegetable consumption was observed among men, that was not statistically significant.

CONCLUSION

Our findings confirm that cigarette smoking is an important predictor of pancreatic cancer mortality, and identify several other factors that may contribute to increased risk.

Body mass index and colon cancer mortality in a large prospective study

Obesity has been reported to increase the risk of colon cancer, especially in men. The authors examined this relation in the American Cancer Society's Cancer Prevention Study II, a nationwide mortality study of US adults. After 12 years of follow-up, 1,616 deaths from colon cancer in women and 1,792 in men were observed among 496,239 women and 379,167 men who were cancer free at enrollment in 1982. The authors used Cox proportional hazards analyses to control for effects of age, race, education, smoking, exercise, alcohol, parental history of colon cancer, fat intake, vegetable and grain intake, aspirin use and, in women, estrogen replacement therapy. In men, death rates from colon cancer increased across the entire range of body mass index (BMI). The rate ratio was highest for men with BMI > or =32.5 (rate ratio (RR) = 1.90, 95% confidence interval (CI): 1.46, 2.47) compared with men with BMI between 22.00 and 23.49. In women, a weaker association was seen in the three BMI categories of 27.5-29.9 (RR = 1.26, 95% CI: 1.03, 1.53), 30.0-32.4 (RR = 1.37, 95% CI: 1.09, 1.72), and > or =32.5 (RR = 1.23, 95% CI: 0.96, 1.59). These prospective data support the hypothesis that obesity increases the risk of colon cancer death and that the relation is stronger and more linear in men than in women.

Passive smoking exposure and female breast cancer mortality

BACKGROUND

Several studies have reported positive associations between environmental tobacco smoke (ETS) and increased risk of breast cancer. However, studies of active smoking and risk of breast cancer are equivocal and in general do not support a positive association. To try to resolve this paradox, we examined the association between breast cancer mortality and potential ETS exposure from spousal smoking in an American Cancer Society prospective study of U.S. adult women.

METHODS

We assessed breast cancer death rates in a cohort of 146 488 never-smoking, single-marriage women who were cancer free at enrollment in 1982. Breast cancer death rates among women whose husbands smoked were compared with those among women married to men who had never smoked. Cox proportional hazards modeling was used to control for potential risk factors other than ETS exposure.

RESULTS

After 12 years of follow-up, 669 cases of fatal breast cancer were observed in the cohort. Overall, we saw no association between exposure to ETS and death from breast cancer (rate ratio [RR] = 1.0; 95% confidence interval [CI] = 0.8-1.2). We did, however, find a small, not statistically significant increased risk of breast cancer mortality among women who were married before age 20 years to smokers (RR = 1. 2; 95% CI = 0.8-1.8).

CONCLUSIONS

In contrast to the results of previous studies, this study found no association between exposure to ETS and female breast cancer mortality. The results of our study are particularly compelling because of its prospective design as compared with most earlier studies, the relatively large number of exposed women with breast cancer deaths, and the reporting of exposure by the spouse rather than by proxy.

Methodological issues in estimating smoking-attributable mortality in the United States

The authors explored two methodological issues in the estimation of smoking-attributable mortality for the United States. First, age-specific and age-adjusted relative risk, attributable fraction, and smoking-attributable mortality estimates obtained using data from the American Cancer Society's second Cancer Prevention Study (CPS II), a cohort study of 1.2 million participants (1982-1988), were compared with those obtained using a combination of data from the National Mortality Follow-back Survey (NMFS), a representative sample of US decedents in which information was collected from informants (1986), and the National Health Interview Survey (NHIS), a nationally representative household survey (1987). Second, the potential for residual confounding of the disease-specific age-adjusted smoking-attributable mortality estimates was addressed with a model-based approach. The estimated smoking-attributable mortality based on the CPS II for the four most common smoking-related diseases-lung cancer, chronic obstructive pulmonary disease, coronary heart disease, and cerebrovascular disease-was 19% larger than the estimated smoking-attributable mortality based on the NMFS/NHIS, yet the two data sources yielded essentially the same smoking-attributable mortality estimate for lung cancer alone. Further adjustment of smoking-attributable mortality for disease-appropriate confounding factors (education, alcohol intake, hypertension status, and diabetes status) indicated little residual confounding once age was taken into account.

Health risks associated with cigar smoking

This article summarizes principal findings from a conference convened by the American Cancer Society in June 1998 to examine the health risks of cigar smoking. State-of-the-science reports were presented and 120 attendees (representing government and private agencies, academia, health educators, and tobacco control experts) participated in panels and summary development discussions. The following conclusions were reached by consensus: (1) rates of cigar smoking are rising among both adults and adolescents; (2) smoking cigars instead of cigarettes does not reduce the risk of nicotine addiction; (3) as the number of cigars smoked and the amount of smoke inhaled increases, the risk of death related to cigar smoking approaches that of cigarette smoking; (4) cigar smoke contains higher concentrations of toxic and carcinogenic compounds than cigarettes and is a major source of fine-particle and carbon monoxide indoor air pollution; and (5) cigar smoking is known to cause cancers of the lung and upper aerodigestive tract. JAMA. 2000;284:735-740

Smoking vs other risk factors as the cause of smoking-attributable deaths: confounding in the courtroom

CONTEXT

The surgeon general estimates that more than 400,000 deaths are attributable to smoking annually in the United States. The tobacco industry has criticized the surgeon general's estimates because they do not control for the lower educational and socioeconomic status of modern-day smokers.

OBJECTIVE

To determine whether controlling for education, occupation, race, alcohol consumption, and various dietary factors, in addition to age and sex, substantially alters the relative and attributable risk estimates associated with tobacco smoking.

DESIGN, SETTING, AND PARTICIPANTS

Nationwide American Cancer Society prospective cohort study of 974, 150 US adults aged 30 years or older, enrolled in 1982 and followed up through 1988. (The same study is used for the surgeon general and Centers for Disease Control and Prevention [CDC] estimates of smoking-attributable deaths in the United States.)

MAIN OUTCOME MEASURES

Death from each of the chronic diseases considered in the CDC's estimate of smoking-attributable mortality (cancers of the lung, oropharynx, larynx, esophagus, pancreas, kidney, bladder, and cervix; ischemic heart disease, arterial disease, and other heart conditions; stroke; chronic obstructive pulmonary disease; and other respiratory conditions). Estimates adjusted for multiple covariates were compared with those adjusted for age only among current and former vs never smokers.

RESULTS

Adjusting for multiple covariates slightly decreased the relative and attributable risk estimates for current smoking in both men and women, but slightly increased the estimates for former smoking in women. Multivariate adjustment decreased the overall estimate of deaths attributable to smoking in the United States by approximately 1%, from 401,109 to 396,741 per year.

CONCLUSIONS

Our study suggests that federal estimates of deaths caused by smoking are not substantially altered by adjustment for behavioral and demographic factors associated with smoking beyond the current adjustment for age and sex. JAMA. 2000;284:706-712

Multivitamin use and mortality in a large prospective study

To determine the relation between multivitamin use and death from heart disease, cerebrovascular disease, and cancer, the authors examined a prospective cohort of 1,063,023 adult Americans in 1982-1989 and compared the mortality of users of multivitamins alone; vitamin A, C, or E alone; and multivitamin and vitamin A, C, or E in combination with that of vitamin nonusers by using multivariate Cox proportional hazard models. Multivitamin users had heart disease and cerebrovascular disease mortality risks similar to those of nonusers, whereas combination users had mortality risks that were 15% lower than those of nonusers. Multivitamin and combination use had minimal effect on cancer mortality overall, although mortality from all cancers combined was increased among male current smokers who used multivitamins alone (relative risk (RR) = 1.13, 95% confidence interval (CI): 1.05, 1.23) or in combination with vitamin A, C, or E (RR = 1.16, 95% CI: 1.06, 1.26), but decreased in male combination users who had never (RR = 0.86, 95% CI: 0.74, 0.99) or had formerly (RR = 0.90, 95% CI: 0.82, 0.98) smoked. No such associations were seen in women. These observational data provide limited support for the hypothesis that multivitamin use in combination with vitamin A, C, or E may reduce heart disease and cardiovascular disease mortality, but add to concerns raised by randomized studies that some vitamin supplements may adversely affect male smokers.

Validation of the American Cancer Society Cancer Prevention Study II Nutrition Survey Cohort Food Frequency Questionnaire

We assessed the validity and reproducibility of a self-administered 68-item food frequency questionnaire completed in 1992-1993 by approximately 185,000 adults. Four hundred forty-one participants completed four 24-hour dietary recall interviews over a 1-year period and a repeat administration of the food frequency questionnaire. For 20 nutrients and 10 food groups, measured nutrient intakes, but not food group intakes, were consistently lower by food frequency questionnaire than by recall. Energy-adjusted, attenuation-corrected Pearson validity correlations ranged from 0.12 to 0.80, with a median of 0.58. Reproducibility measures were generally high, with a median of 0.69. The food frequency questionnaire performed similarly to food frequency questionnaires used in other cohort studies, indicating similar ability to examine diet-disease relations.

Patterns of inpatient surgeries for the top four cancers in the United States, National Hospital Discharge Survey, 1988-95

BACKGROUND

At a time when the population is aging and medical practices are rapidly changing, ongoing surveillance of surgical treatments for cancer is valuable for health services planning.

METHODS

We used data from the National Hospital Discharge Survey for patients with discharge diagnoses of lung, prostate, female breast, and colorectal cancer during 1988-95 to estimate population-based rates and numbers of inpatient surgical procedures.

RESULTS

In 1988-91, rates of lobectomy for lung cancer were significantly higher in males than females. By 1994-95, the male/female differences had largely disappeared due to increasing trends among females and decreasing trends among males. During 1988-95, surgeries on the large intestine for colorectal cancer, including right hemicolectomy and sigmoidectomy, decreased significantly, as did abdominoperineal resections of the rectum. Anterior resections of the rectum increased significantly. Radical prostatectomies for prostate cancer increased from 34,000 in 1988-89 to 104,000 in 1992-93 and then decreased to 87,000 in 1994-95; rates followed a similar pattern. Finally, the number and rates of inpatient mastectomies for female breast cancer decreased over the study period (from 219,000 to 180,000 and from 78.8 to 61.5 per 100,000, respectively).

CONCLUSION

These trends in inpatient surgeries for the major cancers in the US probably reflect changes in disease occurrence and modified treatment recommendations.

Cigar smoking in men and risk of death from tobacco-related cancers

BACKGROUND

Cigar consumption in the United States has increased dramatically since 1993, yet there are limited prospective data on the risk of cancer associated with cigar smoking. We examined the association between cigar smoking and death from tobacco-related cancers in a large, prospective cohort of U. S. men.

METHODS

We used Cox proportional hazards models to analyze the relationship between cigar smoking at baseline in 1982 and mortality from cancers of the lung, oral cavity/pharynx, larynx, esophagus, bladder, and pancreas over 12 years of follow-up of the American Cancer Society's Cancer Prevention Study II cohort. A total of 137 243 men were included in the final analysis. Women were not included because we had no data on their cigar use. We excluded men who ever smoked cigarettes or pipes and adjusted all rate ratio (RR) estimates for age, alcohol use, and use of snuff or chewing tobacco.

RESULTS

Current cigar smoking at baseline, as compared with never smoking, was associated with an increased risk of death from cancers of the lung (RR = 5.1; 95% confidence interval [CI] = 4.0-6.6), oral cavity/pharynx (RR = 4.0 [95% CI = 1.5-10.3]), larynx (RR = 10.3 [95% CI = 2.6-41.0]), and esophagus (RR = 1.8; 95% CI = 0.9-3.7). Although current cigar smokers overall did not appear to be at an increased risk of death from cancer of the pancreas (RR = 1.3; 95% CI = 0.9-1.9) or bladder (RR = 1.0; 95% CI = 0.4-2.3), there was an increased risk for current cigar smokers who reported that they inhaled the smoke (for pancreas, RR = 2.7; 95% CI = 1.5-4.8; for bladder, RR = 3.6; 95% CI = 1.3-9.9).

CONCLUSIONS

Results from this large prospective study support a strong association between cigar smoking and mortality from several types of cancer.

Why is environmental tobacco smoke more strongly associated with coronary heart disease than expected? A review of potential biases and experimental data

Despite exposure levels estimated to be equivalent to smoking only 0. 1-1.0 cigarettes per day, exposure to environmental tobacco smoke (ETS) is estimated to increase the risk of death from coronary heart disease (CHD) between 25 and 35% above the risk of nonexposed persons. This surprisingly large risk associated with a seemingly small exposure has raised doubts about the validity of attributing the increased CHD risk to ETS exposure. This paper reviews various biases that have been hypothesized to account for the increased CHD risk associated with ETS in the epidemiologic studies and characterizes the adverse effects of ETS on thrombosis, vascular endothelium, and exercise tolerance observed in experimental studies of humans and laboratory animals. None of the identified factors that has been proposed to introduce a spurious association between ETS and heart disease seem to invalidate the epidemiologic findings, either separately or in combination. In addition, experimental studies of ETS and heart disease demonstrate that acute exposure of humans and other species to ETS affects platelet function, vascular endothelium, and myocardial exercise tolerance at exposure concentrations widely prevalent in the workplace. Because exposure to ETS affects multiple physiologic pathways, it appears biologically plausible that ETS could cause the substantial increase in CHD risk that has been observed in epidemiologic studies.

Deaths from hematopoietic and other cancers in relation to permanent hair dye use in a large prospective study (United States)

OBJECTIVES

To assess in a large prospective study whether women who used permanent hair dye, especially dark dye for many years, experienced increased death rates from hematopoietic and other cancers that have been associated with hair dye use in some previous reports.

METHODS

In 1982, 547,586 women provided information on use of permanent hair dye and other lifestyle factors when enrolled in an American Cancer Society (ACS) prospective study. We extended mortality follow-up from 7 to 12 years. Using Cox proportional hazards modeling we compared death rates from hematopoietic and other cancers among women according to their hair dye use at baseline with death rates in unexposed women.

RESULTS

The adjusted death rate from all cancers combined was marginally lower among women who ever used hair dye than nonusers (relative risk [RR] = 0.9; 95% confidence interval [CI] = 0.9-1.0). Mortality from all hematopoietic cancers was marginally higher among users than nonusers (RR = 1.1; CI = 1.0-1.2), and increased with an index that combined duration of use and darker coloration (test of trend p = 0.02). Women who used black or brown dye for 10 or more years experienced somewhat higher death rates from non-Hodgkin's lymphoma and (for black dye only) multiple myeloma. The temporal increase in death rates from non-Hodgkin's lymphoma and multiple myeloma between 1982-88 and 1989-94 was similar for women in our study who never used hair dyes to the increase among all US women.

CONCLUSIONS

If prolonged use of dark permanent hair dyes contributes to death rates from non-Hodgkin's lymphoma and multiple myeloma, then the increase is small and difficult to detect reliably even in large prospective studies. The use of permanent hair dye is unlikely to be a major contributor to the temporal rise in non-Hodgkin's lymphoma and multiple myeloma in the US.