Genevieve M. Matanoski

Arsenic in drinking water and lung cancer: A systematic review

Exposure to inorganic arsenic via drinking water is a growing public health concern. We conducted a systematic review of the literature examining the association between arsenic in drinking water and the risk of lung cancer in humans. Towards this aim, we searched electronic databases for articles published through April 2006. Nine ecological studies, two case-control studies, and six cohort studies were identified. The majority of the studies were conducted in areas of high arsenic exposure (100 microg/L) such as southwestern Taiwan, the Niigata Prefecture, Japan, and Northern Chile. Most of the studies reported markedly higher risks of lung cancer mortality or incidence in high arsenic areas compared to the general population or a low arsenic exposed reference group. The quality assessment showed that, among the studies identified, only four assessed arsenic exposure at the individual level. Further, only one of the ecological studies presented results adjusted for potential confounders other than age; of the cohort and case-control studies, only one-half adjusted for cigarette smoking status in the analysis. Despite these methodologic limitations, the consistent observation of strong, statistically significant associations from different study designs carried out in different regions provide support for a causal association between ingesting drinking water with high concentrations of arsenic and lung cancer. The lung cancer risk at lower exposure concentrations remains uncertain.

Heavy Phenacetin Use and Bladder Cancer in Women Aged 20 to 49 Years

We investigated the use of analgesics containing phenacetin or acetaminophen in 173 young women with urinary bladder cancer and 173 matched controls. The cases, who were 20 to 49 years old at the time of diagnosis of cancer, were 6.5 times more likely to report regular use of analgesics containing phenacetin at least one year before diagnosis than were their matched controls (odds ratio, 6.5; 95 per cent confidence interval, 1.5 to 59.2). Among the 15 women (13 cases and 2 controls) reporting regular use of phenacetin-containing drugs, 8 of the cases and 1 of the controls reported daily use for over one year (P = 0.04). Excessive use of analgesics containing acetaminophen was not reported. The increased risk of bladder cancer in young women who regularly used phenacetin-containing products remained present after adjustments for all other identified risk factors.

The Potential Adverse Health Effects of Dental Amalgam

There is significant public concern about the potential health effects of exposure to mercury vapour (Hg0) released from dental amalgam restorations. The purpose of this article is to provide information about the toxicokinetics of Hg0, evaluate the findings from the recent scientific and medical literature, and identify research gaps that when filled may definitively support or refute the hypothesis that dental amalgam causes adverse health effects.Dental amalgam is a widely used restorative dental material that was introduced over 150 years ago. Most standard dental amalgam formulations contain approximately 50% elemental mercury. Experimental evidence consistently demonstrates that Hg0 is released from dental amalgam restorations and is absorbed by the human body. Numerous studies report positive correlations between the number of dental amalgam restorations or surfaces and urine mercury concentrations in non-occupationally exposed individuals. Although of public concern, it is currently unclear what adverse health effects are caused by the levels of Hg0 released from this restoration material. Historically, studies of occupationally exposed individuals have provided consistent information about the relationship between exposure to Hg0 and adverse effects reflecting both nervous system and renal dysfunction. Workers are usually exposed to substantially higher Hg0 levels than individuals with dental amalgam restorations and are typically exposed 8 hours per day for 20–30 years, whereas persons with dental amalgam restorations are exposed 24 hours per day over some portion of a lifetime. This review has uncovered no convincing evidence pointing to any adverse health effects that are attributable to dental amalgam restorations besides hypersensitivity in some individuals.

Cancer and other causes of mortality among radiologic technologists in the United States.

Data are limited on the role of chronic exposure to low‐dose ionizing radiation in the etiology of cancer. In a nationwide cohort of 146,022 U.S. radiologic technologists (73% female), we evaluated mortality risks in relation to work characteristics. Standardized mortality ratios (SMRs) were computed to compare mortality in the total cohort vs. the general population of the United States. Mortality risks were low for all causes (SMR = 0.76) and for all cancers (SMR = 0.82) among the radiologic technologists. We also calculated relative risks (RR) for the 90,305 technologists who responded to a baseline mailed questionnaire, using Poisson regression models, adjusted for known risk factors. Risks were higher for all cancers (RR = 1.28, 95% confidence interval [CI] = 0.93–1.69) and breast cancer (RR = 2.92, 95% CI = 1.22–7.00) among radiologic technologists first employed prior to 1940 compared to those first employed in 1960 or later, and risks declined with more recent calendar year of first employment (p‐trend = 0.04 and 0.002, respectively), irrespective of employment duration. Risk for the combined category of acute lymphocytic, acute myeloid and chronic myeloid leukemias was increased among those first employed prior to 1950 (RR = 1.64, 95% CI = 0.42–6.31) compared to those first employed in 1950 or later. Risks rose for breast cancer (p‐trend = 0.018) and for acute lymphocytic, acute myeloid and chronic myeloid leukemias (p‐trend = 0.05) with increasing duration of employment as a radiologic technologist prior to 1950. The elevated mortality risks for breast cancer and for the combined group of acute lymphocytic, acute myeloid and chronic myeloid leukemias are consistent with a radiation etiology given greater occupational exposures to ionizing radiation prior to 1950 than in more recent times.

Adulthood consumption of preserved and nonpreserved vegetables and the risk of nasopharyngeal carcinoma: a systematic review.

The incidence rates of nasopharyngeal carcinoma (NPC) are dramatically higher in certain regions of Asia compared to the rest of the world. Few risk factors for NPC are known; however, in contrast to the hypothesized health benefits of nonpreserved vegetables, it is thought that preserved vegetable intake may play a role in contributing to the higher incidence of NPC in high‐risk regions. Therefore, the purpose of this study was to systematically review the epidemiologic evidence on the associations between adulthood intake of preserved and nonpreserved vegetables and NPC risk. A search of the epidemiological literature from 1966 to 2004 was performed using several bibliographic databases, including PubMed and the Chinese Biomedical Literature Database System. There were no language restrictions. Meta‐analysis was conducted to obtain pooled odds ratios (ORs) for the highest‐versus‐lowest categories of preserved and nonpreserved vegetable intake. A total of 16 case‐control studies were identified in the search. Results showed that highest‐versus‐lowest preserved vegetable intake was associated with a 2‐fold increase in the risk of NPC (Random Effects Odds Ratio (RE OR) 2.04; 95% Confidence Limits (CL) 1.43, 2.92). Conversely, high nonpreserved vegetable intake was associated with 36% decrease in the risk of NPC (RE OR 0.64; 95% CL 0.48, 0.85). Findings for both preserved and nonpreserved vegetables were consistent across vegetable type and by country of study. Further research in high‐risk areas to gain insight into the risk associated with preserved vegetables and protection associated with nonpreserved vegetables may advance understanding of NPC and yield clues for prevention.

Inner-city women at risk for cervical cancer: behavioral and utilization factors related to inadequate screening.

This study investigated the relationships between health care utilization, knowledge, attitudes, sociodemographic characteristics, and adequacy of cervical cancer screening among a random sample of women from inner-city neighborhoods with high rates of cervical cancer mortality. Of 416 women interviewed, 30.3% reported hysterectomies; women with intact uteri (N = 290) are the subjects of this analysis. Over two-fifths (44.1%) reported not receiving adequate Pap testing during the previous 4 years. Compared with adequately screened women, they were more likely to be 45 years or older, have no medical insurance, report never having been to an obstetrician-gynecologist, recall never having been told by a medical provider how often to get a Pap test, rely on providers for adequate screening, report not seeking care as often as they think they should, have less knowledge of risk factors for cervical cancer, and believe that women should get Pap tests less than yearly. Separate models for younger and older women showed that these factors vary by age, demonstrating the need for interventions to be sensitive to age subgroups. These findings suggest that cancer control activities should place more emphasis on motivating women as well as influencing the health care delivery system to maximize reductions in cervical cancer.

Descriptive epidemiology of vaginal cancer incidence and survival by race, ethnicity, and age in the United States†‡

Vaginal cancer is a rare malignancy. It has many of the same risk factors as cervical cancer, including a strong association with persistent human papillomavirus infection. Descriptive studies of the epidemiology of vaginal cancer are scarce in the literature.

Incidence of childhood cancer in twins

The incidence of childhood cancer in twins was evaluated by linking a roster of 30,925 twins born in Connecticut (United States) between 1930 and 1969 with the Connecticut Tumor Registry. Cancer, exclusive of nonmelanoma skin cancer, was identified in 19 females and 12 males under 15 years of age. The incidence rate among twins was 7.9 cancers per 100,000 person-years (PY) overall, and 9.7 and 6.1 per 100,000 PYs for females and males, respectively. Four of 13 leukemias occurred in two female twin pairs, representing concordance rates of 18 percent overall and 29 percent for like-sex pairs, which are somewhat higher than values reported previously. The number of cancers expected was computed on the assumption that twins experienced the same sex-, age-, and calendar time-specific cancer rates as recorded for all Connecticut-born children. Because active follow-up of individuals was not conducted, an adjustment to person-years of observation was made to account for childhood mortality, including the high perinatal mortality characteristie of twins. Childhood cancer was 30 percent less frequent than expected (standardized incidence ratio [SIR]=0.7; 95 percent confidence interval [CI]=0.5–0.9), a deficit that is marginally greater than those found in previous studies. Both leukemia (SIR=0.8; CI=0.4–1.4), and all other cancers combined (SIR=0.6; CI=0.3–0.9) occurred less often than expected. The deficit was greater among males (SIR=0.5; CI=0.2–0.8) than among females (SIR=0.9; CI=0.5–1.4) and was especially pronounced among males younger than five years (SIR=0.2; CI=0.0–0.7). The data support the view that twins, particularly male twins, have a lower risk of childhood cancer than single-born children. Any added risk for twins associated with their greater frequency of exposure to prenatal X-rays appears to have been insufficient to offset an ‘effect’ of twinning per se. Possible explanations for this finding include (i) the low birthweight distribution of twins, or (ii) selective early mortality of twin fetuses or neonates who would otherwise have developed a clinical cancer.

Body fat patterning in women with endometrial cancer

It has long been known that the risks of some cancers, including endometrial, are associated with obesity. Recent evidence suggests that body fat distribution patterns also affect the risk of developing some diseases. A question that remains is whether cancers are associated with specific distributions of body fat. In this study, women with endometrial cancer were compared to community controls of similar age and race. Participants were interviewed and then measured to determine fat distribution patterns defined by the waist-to-hip circumference ratio. Women with upper body fat distribution had a 3.2-fold (95% confidence limits 1.2, 8.9) higher risk of endometrial cancer than women with lower body fat distribution even with correction for age, parity, and smoking. Obese women with an upper body fat pattern had a 5.8-fold (confidence limits 1.7, 19.9) higher risk of endometrial cancer than nonobese/lower body fat patterned women. Obese women who never smoked had a 3.3-fold statistically significant higher risk of endometrial cancer than nonobese women who never smoked. Current smokers had lower risks than their nonsmoking counterparts. The 3-fold increased risk of endometrial cancer associated with upper body fat did not disappear with adjustment for obesity and smoking.

Cancer mortality among white males in the meat industry

A study was conducted among 13,844 members of a meat-cutters union, from July 1949 to December 1980, to examine cancer occurrence in the meat industry. Separate analyses were carried out for the whole group, and for subgroups defined by job-categories characteristic of the industry, including a control group. Mortality was compared with that of the United States through the estimation of standardized mortality ratios (SMR) and proportional mortality ratios. A statistically significant proportional mortality ratio of 2.9 was obtained for Hodgkins disease among abattoir workers; the SMR of 2.2 was not significant. Among meat-packing plant workers, highly statistically significant SMRs were recorded for bone cancer, SMR = 9.6; cancer of the buccal cavity and pharynx, SMR = 3.4; and lung cancer, SMR = 1.9. The role of oncogenic viruses and other carcinogenic exposures was investigated.