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Biomedical subjects

C F Lynch

Publications and source records attributed to C F Lynch.

At least 73 records · Page 4Linked to original sources
PubMed1997

Intrauterine growth retardation in Iowa communities with herbicide-contaminated drinking water supplies.

In a statewide survey of 856 Iowa municipal drinking water supplies in 1986-1987 the Rathbun rural water system was found to contain elevated levels of triazine herbicides. Rates of low birth weight, prematurity, and intrauterine growth retardation (IUGR) in live singleton births during the period 1984-1990 by women living in 13 communities served by the Rathbun water system were compared to other communities of similar size in the same Iowa counties. The Rathbun communities had a greater risk of IUGR than southern Iowa communities with other surface sources of drinking water (relative risk = 1.8; 95% CI = 1.3, 2.7). Multiple linear regression analyses revealed that levels of the herbicides atrazine, metolachlor, and cyanzinc were each significant predictors of community IUGR rates in southern Iowa after controlling for several potentially confounding factors including maternal smoking and socioeconomic variables. The association with IUGR was strongest for atrazine, but all three herbicides were intercorrelated and the independent contributions of each to IUGR risk could not be determined. We conclude that communities in southern Iowa with drinking water supplies contaminated with herbicides have elevated rates of IUGR compared to neighboring communities with different water supplies. Because of the limitations of the ecologic design of this study, including aggregate rather than individual measures of exposure and limited ability to control for confounding factors related to source of drinking water and risk of IUGR, a strong causal relationship between any specific water contaminant and risk of IUGR cannot yet be inferred. The association between the water supplied to the Rathbun communities and the increased risk of IUGR should be considered a preliminary finding that needs to be verified by more detailed epidemiologic studies.

Atrazine↗
PubMed1997

The effect of gender and age at onset of depression on mortality.

BACKGROUND: Depression has a marked negative impact on geriatric patient mortality and morbidity. The risk factors and exact reasons for these effects are not well understood. METHOD: Seeking to better define the factors, we retrospectively analyzed the effects of gender and age at onset of affective disorder in a naturalistic study of 192 geriatric patients consecutively admitted to a large midwestern tertiary care center between 1980 and 1987 for the treatment of unipolar depression. RESULTS: After controlling for age at index admission, patients with an onset of depression before age 40 suffered significantly (p < .05) less mortality in follow-up than those with onset after age 40. When effects of gender are examined, the effects of age at onset are most profound in women, with a threefold increase in the rate of death in the cohort with age at onset of depression after 70 years when compared to those with onset before age 40. CONCLUSION: These results and those of others suggest that depressed elderly women with no previous history of affective disorder are at a markedly increased risk compared with elderly women with a history of affective illness for morbidity and mortality and that a significant proportion of elderly depressed patients are admitted to a psychiatric hospital for a depression that is secondary to serious medical illness.

Age Factors↗
PubMed1996

Exogenous sex hormone use, correlates of endogenous hormone levels, and the incidence of histologic types of sarcoma of the uterus.

BACKGROUND: We analyzed data from a population-based, multi-center, case-control study to determine whether the occurrence of histologic types of uterine sarcoma is related to exogenous hormone use and/or to two correlates of endogenous estrogens: excess weight and cigarette smoking. METHODS: One hundred sixty-seven women with newly-diagnosed uterine sarcoma (56 leiomyosarcoma, 85 mixed mullerian tumors, and 26 endometrial stromal sarcomas) were interviewed by telephone regarding possible risk factors for these neoplasms, For comparison, 208 women identified at random from the general population of the study areas were interviewed as controls. RESULTS: Use of oral contraceptives was positively associated with the risk of leiomyosarcoma (odds ratios [OR] = 1.7, 95% confidence interval [CI] = 0.7, 4.1), primarily among women who last used these medications 15 or more years prior to diagnosis. Use of noncontraceptive estrogens was directly associated with the risk of mixed mullerian tumors, but only among recent and long-term users of these medications. Women in the highest quantile of body mass index (> or = 27.5 kg/m2) one year prior to diagnosis were at increased risk of each type of uterine sarcoma (leiomyosarcoma, OR = 2.5, 95% CI = 1.1, 5.7; mixed mullerian tumors, OR = 2.9, 95% CI = 1.3, 6.7; stromal sarcoma, OR = 3.5, 95% CI = 1.1, 10.9). Women who had ever smoked cigarettes were at reduced risk of leiomyosarcoma (OR = 0.6, 95% CI = 0.3, 1.1) and stromal sarcoma (OR = 0.5, 95% CI = 0.2, 1.2), but the relationship was not more pronounced among heavy smokers; no association with smoking was observed with mixed mullerian tumors. CONCLUSIONS: Several of these findings parallel those from studies of endometrial carcinoma and may indicate a role for unopposed estrogen in the etiology of histologic types of uterine sarcoma.

Adolescent↗
PubMed1996

Risk factors for advanced-stage oral cavity cancer.

OBJECTIVE: To assess the association between risk factors for inadequate surveillance of oral cavity cancer and stage of disease (localized, T1, T2/N0 vs advanced, T1, T2/N1-3, T3, T4/N0 or N1-3). DESIGN: Convenience sample from a case series. SETTING: Otolaryngology clinic in a tertiary care hospital. PARTICIPANTS: Fifty-three patients with cancer of the oral cavity who were treated at The University of Iowa, Iowa City, from October 1990 through March 1994, participated in the study. Selection criteria included pathologic confirmation of squamous cell carcinoma (SCC) of the oral cavity, the capacity to retrieve data regarding tumor characteristics at initial presentation, and completion of a 30-item questionnaire by the patient. INTERVENTION: Administration of questionnaire identifying factors contributing to inadequate surveillance of cancer of the oral cavity. OUTCOME MEASUREMENTS: Advanced-stage cancer of the oral cavity was identified by the presence of large tumors (T3, T4) and cancer metastatic to the neck lymph nodes (N1, N2, N3). Comparison groups were built to determine the relationship between these two dependent variables and multiple independent variables. Descriptive statistics and tests of association were used to assess relationships. RESULTS: Two of the 53 patients performed self oral examinations specifically designed to screen for cancer prior to finding cancer of the oral cavity. Knowledge of the warning signs of cancer of the oral cavity was denied by 87%. The rate of cancer growth in the oral cavity was variable from first discovery by the patient to the time of tumor staging by otolaryngologists. The interval from discovery of the tumor to tumor staging (delay in diagnosis) was greatest for floor of the mouth cancers and shortest for those cancers located on the tongue. Thirty-seven percent of the patients younger than age 64 years were edentulous in contrast to 62% edentulism in patients older than 65 years. There was a significant, inverse relationship between time since last dental visit and late-stage disease. CONCLUSIONS: Patients with advanced-stage cancer of the oral cavity tended to be elderly, more often wore dentures, and seldom visited the dentist. Treatment of cancer of the oral cavity as localized disease, with an associated decrease in morbidity and mortality, is likely to result by targeting this population as one in need of more intense surveillance.

Age Factors↗
PubMed1996

Method to electronically collect emergency department data.

STUDY OBJECTIVE: To describe the development and completeness of an electronic injury-surveillance system, the Rural Injury Surveillance System (RISS). METHODS: The emergency departments of nine rural Iowa hospitals submitted information on all patients treated from May 1993 through June 1994. RESULTS: The EDs submitted information on 23,594 patients with 32,445 different injury, disease, or follow-up visits. On the basis of comparison with the handwritten ED logbook, 90% of visits were also available in the RISS. Of the visits recorded in the RISS, 99% were also recorded in the logbook. The proportion of missing diagnostic codes decreased from a high of 22.6% in May 1993 to 8.1% in June 1994. The proportion of missing external cause codes was about 25% at the end of the study period. The proportion of missing industry and occupational codes was less than 5% at the end of the study period. CONCLUSION: Our findings show that complete, computerized, ED-based injury surveillance in rural EDs is possible and should be developed further.

Data Collection↗
PubMed1996

Injuries among construction workers in rural Iowa: emergency department surveillance.

Surveillance of all emergency department admissions for nine rural hospitals identified visits for injuries by 189 employed patients with construction occupations out of a total of 1843 injury visits of all employed patients with known occupations. The injury rate for construction workers was 20.28 injuries per 100 workers per year-more than 2.5 times that of all other employed people. The work-related injury rate was 7.63 per 100 construction workers, more than four times that of all other employed people. The injuries of construction workers seen in the emergency department were primarily open wounds, fractures and dislocations, and contusions, injuries similar to those of other workers. The percentage of work-related burns was higher in construction workers than for other workers, particularly because of burns to roofers and laborers from tar or hot fluids and flash burns from welding.

Adult↗
PubMed1996

The Agricultural Health Study.

The Agricultural Health Study, a large prospective cohort study has been initiated in North Carolina and Iowa. The objectives of this study are to: 1) identify and quantify cancer risks among men, women, whites, and minorities associated with direct exposure to pesticides and other agricultural agents; 2) evaluate noncancer health risks including neurotoxicity reproductive effects, immunologic effects, nonmalignant respiratory disease, kidney disease, and growth and development among children; 3) evaluate disease risks among spouses and children of farmers that may arise from direct contact with pesticides and agricultural chemicals used in the home lawns and gardens, and from indirect contact, such as spray drift, laundering work clothes, or contaminated food or water; 4) assess current and past occupational and nonoccupational agricultural exposures using periodic interviews and environmental and biologic monitoring; 5) study the relationship between agricultural exposures, biomarkers of exposure, biologic effect, and genetic susceptibility factors relevant to carcinogenesis; and 6) identify and quantify cancer and other disease risks associated with lifestyle factors such as diet, cooking practices, physical activity, smoking and alcohol consumption, and hair dye use. In the first year of a 3-year enrollment period, 26,235 people have been enrolled in the study, including 19,776 registered pesticide applicators and 6,459 spouses of registered farmer applicators. It is estimated that when the total cohort is assembled in 1997 it will include approximately 75,000 adult study subjects. Farmers, the largest group of registered pesticide applicators comprise 77% of the target population enrolled in the study. This experience compares favorably with enrollment rates of previous prospective studies.

Adult↗
PubMed1996

Evaluation of mortality and cancer incidence among alachlor manufacturing workers.

Alachlor is the active ingredient in a family of preemergence herbicides. We assessed mortality rates from 1968 to 1993 and cancer incidence rates from 1969 to 1993 for manufacturing workers with potential alachlor exposure. For workers judged to have high alachlor exposure, mortality from all causes combined was lower than expected [23 observed, standardized mortality ratio (SMR) = 0.7, 95% CI, 0.4-1.0], cancer mortality was similar to expected (6 observed, SMR = 0.7, 95% CI, 0.3-1.6), and there were no cancer deaths among workers with 5 or more years high exposure and 15 or more years since first exposure (2.3 expected, SMR = 0, 95% CI, 0-1.6). Cancer incidence for workers with high exposure potential was similar to the state rate [18 observed, standardized incidence ratio (SIR) = 1.2, 95% CI, 0.7-2.0], especially for workers exposed for 5 or more years and with at least 15 years since first exposure (4 observed, SIR = 1.0, 95% CI, 0.3-2.7). The most common cancer for these latter workers was colorectal cancer (2 observed, SIR 3.9, 95% CI, 0.5-14.2 among workers). Despite the limitations of this study with respect to small size and exposure estimating, the findings are useful for evaluating potential alachlor-related health risks because past manufacturing exposures greatly exceeded those characteristic of agricultural operations. These findings suggest no appreciable effect of alachlor exposure on worker mortality or cancer incidence rates during the study period.

Acetamides↗
PubMed1996

Nasopharyngeal cancer in a low-risk population: defining risk factors by histological type.

Nasopharyngeal cancer (NPC) is a major public health problem in parts of Southeast Asia and North Africa, but is rare among whites and blacks. Although infection with the EBV and genetic susceptibility appear to play large roles in high-incidence populations, migrant studies suggest that environmental factors may also be important. Aside from the high risks associated with ingestion of salted fish, surprisingly few other risk factors have been established from studies in endemic areas. We studied a low-incidence population to determine whether tobacco use, alcohol consumption, and certain medical conditions and treatments are related to NPC and to examine variations in risk by histology. We reasoned that new relationships might be best identified in the absence of strong causal pathways, such as intake of preserved foods and genetic susceptibility. A population-based case-control study was conducted from 1987 to 1993 at five cancer registries in the United States: western Washington, metropolitan Detroit, Connecticut, Iowa, and Utah. Controls were identified by random digit dialing and frequency matched to the gender and age distribution of cases at each registry. Telephone interviews were completed by 231 cases and 246 controls. We observed a strong dose-response relationship between cigarette smoking and risk of differentiated squamous cell carcinoma (test for trend, P < .001). The highest risk [odds ratio (OR), 6.5; 95% confidence interval (CI), 2.0-21.3] occurred among current smokers with a history of more than 60 pack-years. In contrast, there was no evidence that undifferentiated or nonkeratinizing carcinomas were associated with cigarette smoking. Similarly, a significant increase in risk was observed for the heaviest alcohol consumers (21 or more drinks/week) only for differentiated squamous cell carcinomas (OR, 2.9; 95% CI, 1.2-6.9). The associations with cigarettes and alcohol appeared to be stronger among persons 50 years or older. There was a suggestion that diagnosis with infectious mononucleosis (a marker of late infection with EBV) is linked with decreased NPC risk (OR, 0.4; 95% CI, 0.1-1.1). This report indicates that over two-thirds of differentiated squamous cell NPC cases arising in older persons in the United States can be accounted for by cigarettes and alcohol, but leaves unexplained cases arising in the young and carcinomas of undifferentiated or nonkeratinizing histology. Future studies of NPC need to take into account histology and age in evaluating these and other environmental and genetic risk factors.

Adult↗
PubMed1996

Is microstaging of early invasive cancer of the urinary bladder possible or useful?

Reports suggest that it is possible and useful to classify T1 (Stage A) carcinomas of the urinary bladder into subgroups dependent on the depth of invasion as defined by the muscularis mucosae (MM). In an attempt to evaluate the reproducibility of these findings, we reviewed the slides from 77 cases of T1 bladder cancer diagnosed in 1983 in Iowa residents. The cases were identified through a statewide cancer registry. Slides and pathology reports were obtained from the original laboratories. Two pathologists independently evaluated each case, most (74 cases) of which were transurethral resections, for the presence or absence of MM and three levels of invasion (lamina propria, MM, and submucosa). Disagreements were resolved by simultaneous review resulting in a consensus diagnosis. Because of the population-based source, tissue had been obtained by multiple urologists and processed in multiple laboratories, resulting in noticeable variation in quality of material. Interobserver agreement for the level of invasion was poor between the two pathologists (kappa = 0.22; 95% C.I. = 0.08-0.36). Consensus resulted in 34 cases (44.2%) invasive to the lamina propria, 23 (29.9%) to the MM, and 11 (14.3%) to the submucosa. The level was indeterminate in nine (11.7%). All of the 77 cases were followed until death or 1993-95, with 57 patients dying during this interval. There were no significant differences in survival for each level of invasion (lamina propria, MM, submucosa) and the indeterminate cases, as determined by either consensus or individual observer evaluation. Our findings suggest that microstaging of early invasive bladder cancer is technically difficult and, at least in cases derived from various urologists and laboratories, does not yield a prognostically significant separation.

Humans↗
PubMed1995

Second primary cancer after treatment for cervical cancer. An international cancer registries study.

BACKGROUND: The pattern of second cancers after treatment for cervical cancer provides important information on the risk of radiation-induced malignancies. Large numbers of women survive many years and can be studied for late effects. METHODS: Incident second cancers in 86,193 patients with cervical cancer reported to 13 population-based cancer registries in 5 countries were evaluated to estimate the risk of second cancer among very long term survivors. RESULTS: Overall, 7543 second cancers were observed versus 6015 cancers expected based on population rates (observed/expected = 1.2). Lung cancer accounted for nearly half of the excess cancers. Among the 49,828 women treated with radiation, 3750 survived 30 or more years and a two-fold risk of cancers of heavily irradiated organs was seen. Most of the excess cancers were of the rectum, vagina, vulva, ovary, and bladder. Patterns of risk over time since treatment were consistent with a radiation etiology. Significant increases of nonchronic lymphocytic leukemia and cancers of the bone and kidney were also linked to radiotherapy. Women treated surgically were also at significant risk of second cancers, in all likelihood related to cigarette smoking and risk factors similar to those of cervical cancer. CONCLUSIONS: Curative therapy for cervical cancer results in large numbers of long term survivors who develop second cancers very late in life. Radiation is an important cause of this increase and there is no evidence that risk returns to normal levels.

Europe↗
PubMed1995

Bladder and kidney cancer following cyclophosphamide therapy for non-Hodgkin's lymphoma.

BACKGROUND: Cyclophosphamide is an established bladder carcinogen, but few studies have examined the relationship between dose and effect. The largest analysis to date included only seven cases of bladder cancer. No investigation has estimated the risk of kidney cancer. PURPOSE: The purpose of this study was to quantify the risk of bladder and kidney cancer following cyclophosphamide therapy. METHODS: Within a cohort of 6171 two-year survivors of non-Hodgkin's lymphoma (NHL), 48 patients with secondary cancer of the urinary tract were identified and matched to 136 control subjects with NHL who did not develop a second malignancy. Detailed information on chemotherapeutic drugs and cumulative dose received was collected for all subjects. Radiation dose to the target organ was estimated from individual radiotherapy records. Evaluations of the risk of second cancer as a result of treatment with cyclophosphamide alone, radiation alone, or both therapies were made relative to those patients who were exposed to neither treatment modality. RESULTS: A significant 4.5-fold risk of bladder cancer (95% confidence interval [CI] = 1.5-13.6) followed therapy with cyclophosphamide, and risk was dependent upon cumulative dose. Among patients who received a total amount of cyclophosphamide of less than 20 g, a nonsignificant 2.4-fold risk of bladder cancer was apparent. Significantly elevated sixfold (95% CI = 1.3-29) and 14.5-fold (95% CI = 2.3-94) risks of bladder malignancy followed cumulative doses of 20-49 g and 50 g or more, respectively (P value for trend = .004). Radiotherapy given without cyclophosphamide was associated with a nonsignificant increased risk of bladder malignancy. Excess bladder cancer risk following treatment with both radiotherapy and cyclophosphamide was as expected if individual risks were summed. Neither radiotherapy nor cyclophosphamide was associated with excesses of kidney cancer. CONCLUSIONS: Cyclophosphamide-related bladder cancer is dose dependent. For patients given cumulative doses between 20 and 49 g, the absolute risk of bladder cancer is on the order of three excess cancers per 100 NHL patients after 15 years of follow-up. At cumulative doses of 50 g or more, the excess risk increases to approximately seven excess bladder cancers per 100 NHL patients. IMPLICATIONS: The strong dose-response relationship and high absolute risk of bladder cancer underscore the importance of limiting the cumulative dose of cyclophosphamide to what is required to achieve therapeutic end points. The risk of secondary bladder malignancy and other late sequelae of therapy must be carefully weighted against the curative gains provided by cyclophosphamide. Moreover, long-term side effects of therapy that might be acceptable in cancer treatment may need to be re-evaluated for patients with non-neoplastic disorders.

Aged↗
PubMed1995

Urinary system.

BACKGROUND: Although site-specific cancer frequencies and incidence rates for the United States are regularly reported by the National Cancer Institute's (NCI) Surveillance, Epidemiology, and End Results (SEER) program, they have not been reported by histologic type within a specific site. This report presents data for 76,303 cancers of the urinary tract by histologic type. METHODS: Cancer data were obtained from the SEER program. Urinary tract cancers were eligible if they were histologically confirmed, in situ or invasive, and diagnosed between 1973 and 1987. The urinary tract was divided into the following sites: kidney and renal pelvis, ureter, urinary bladder, urethra, and other urinary. Histologic types were evaluated by site, age, sex, race, incidence, and survival. RESULTS: Of the 76,303 cancers, 72.0% were transitional cell carcinomas and 22.0% were adenocarcinomas. Adenocarcinoma was the most common histologic type in the kidney and renal pelvis (also referred to as renal cell carcinoma), whereas transitional cell carcinoma was the most common histologic type in the remainder of the urinary tract. For the more common histologic types, age-adjusted incidence rates were always higher among males than females. CONCLUSIONS: Because adenocarcinomas represent most kidney and renal pelvis cancers and transitional cell carcinomas represent most urinary bladder cancers, these histologic types largely explain incidence and survival trends reported for these two common cancer sites. Future population-based cancer epidemiologic studies should try to focus more on specific histologic types within a cancer site to better clarify risk factors and incidence and survival trends for cancer.

Adult↗
PubMed1995

Effect of ECT on mortality and clinical outcome in geriatric unipolar depression.

BACKGROUND: Recent reports have called into question the safety and effectiveness of electroconvulsive therapy (ECT). METHOD: To investigate these claims, the effects of ECT on clinical outcomes were examined as part of a retrospective, naturalistic study of 192 geriatric patients consecutively admitted between 1980 and 1987 to a large midwestern tertiary care center for the treatment of depression. Data were analyzed by a variety of parametric and nonparametric methods including ANOVA and survival analysis. RESULTS: Patients who received ECT (N = 108) were more likely to exhibit psychomotor retardation and to have had prior courses of ECT than those who did not receive ECT (N = 84). Furthermore, despite the absence of differences in the overall rate or severity of medical comorbidity, patients receiving ECT were more likely to be alive at follow-up and to demonstrate greater clinical improvement than those treated only with pharmacotherapy. CONCLUSION: These results confirm previous studies demonstrating the superior efficacy of ECT as compared with conventional pharmacotherapy treatment in patients hospitalized with depression and document its safety in long-term follow-up.

Age Factors↗
PubMed1994

Risk of leukemia following treatment for non-Hodgkin's lymphoma.

BACKGROUND: There have been few evaluations of the risk of acute nonlymphocytic leukemia (ANLL) following therapy for non-Hodgkin's lymphoma (NHL). Further, the relationship between cumulative dose of cytotoxic drug, radiation dose to active bone marrow, and the risk of ANLL following NHL have not been well described. PURPOSE: Our purpose was to examine the risk of ANLL in relationship to all prior treatment for NHL. METHODS: Within a cohort study of 11,386 2-year survivors of NHL, 35 case patients with secondary ANLL were identified and matched to 140 controls with NHL who did not develop ANLL. The primary eligibility criteria for the cohort included a diagnosis of NHL as a first primary cancer from January 1, 1965, through December 31, 1989; age 18 through 70 years at the time of initial diagnosis; and survival for 2 or more years without the development of a second invasive primary malignancy. Detailed information on chemotherapeutic drugs and radiotherapy was collected for all patients. Standard conditional logistic regression programs were used to estimate the relative risk (RR) of ANLL associated with specific therapies by comparing the exposure histories of case patients with individually matched controls. RESULTS: Significant excesses of ANLL followed therapy with either prednimustine (RR = 13.4; 95% confidence interval [CI] = 1.1-156; P trend for dose < .05) or regimens containing mechlorethamine and procarbazine (RR = 12.6; 95% CI = 2.0-79; P < .05). Elevated risks of leukemia following therapy with chlorambucil were restricted to patients given cumulative doses of 1300 mg or more (RR = 6.5; 95% CI = 1.6-26; P < .05). Cyclophosphamide regimens were associated with a small, nonsignificant increased risk of ANLL (RR = 1.8;95% CI = 0.7-4.9), with most patients receiving relatively low cumulative doses (< 20,000 mg). Radiotherapy given at higher doses without alkylating agents was linked to a nonsignificant threefold risk of ANLL compared with lower dose radiation or no radiotherapy. CONCLUSIONS: Our results suggest that prednimustine may be a human carcinogen, with a positive dose-response gradient evident for ANLL risk. The low, nonsignificant risk of leukemia associated with cyclophosphamide was reassuring because this drug is commonly used today. Despite the excesses of ANLL associated with specific therapies, secondary leukemia remains a rare occurrence following NHL. Of 10,000 NHL patients treated for 6 months with selected regimens including low cumulative doses of cyclophosphamide and followed for 10 years, an excess of four leukemias might be expected.

Aged↗
PubMed1994

Residential radon exposure and lung cancer: evidence of an urban factor in Iowa.

An ecological study of lung cancer, cigarette smoking, and radon exposure was conducted in 20 Iowa counties. County-based lung cancer incidence data for white female residents of Iowa were stratified according to radon level and smoking status. Cancer incidence data for the period 1973-1990 were obtained from the State Health Registry of Iowa. Smoking level was determined from a randomly mailed survey. Radon level was determined according to an EPA supported charcoal canister survey. Within low smoking counties, rates for all lung cancer and small cell carcinoma were significantly lower (p < 0.05) in the high radon counties relative to the medium and low radon counties. However, within high smoking counties, rates for all lung cancer, adenocarcinoma, and small cell carcinoma were significantly higher (p < 0.05) in the high radon counties relative to the low radon counties. Variations in socioeconomic data for these counties, available through the 1980 and 1990 census, did not explain these results. Lung cancer rates also were significantly increased in urban counties even after holding smoking status constant. Multivariate analyses revealed significant interactions between smoking, urbanization, radon levels, and lung cancer. The results of this hypothesis generating study will be tested in a case/control study now ongoing in Iowa. Analysis will need to include separate evaluations by smoking status, radon level, and residence in urban or rural areas for the major morphologic types of lung cancer.

Adenocarcinoma↗
PubMed1994

The driver's license list as a population-based sampling frame in Iowa.

Driver's license lists are infrequently used for population-based sampling, presumably because of suspicions of poor population coverage. The 1990 Iowa driver's license list was compared with the 1990 census to evaluate coverage by 5-year age group, sex, resident county, and urbanicity. Coverage exceeded 90% among 15- to 74-year-old men and 15- to 64-year-old women, with uniform coverage by county and county urbanicity group in these age ranges. In Iowa, these lists are convenient and cost-effective and appear to be representative for 25- to 64-year-olds. The representativeness of driver lists in regard to other factors and in other geographic regions deserves further evaluation.

Adolescent↗