Yating Chen

Time trend and the age-period-cohort effect on the incidence of histologic types of lung cancer in Connecticut, 1960-1989.

Background. Recent epidemiologic studies have suggested changing patterns of lung cancer incidence by histologic type. The observed time trends have been attributed to a change in the rate of cigarette smoking, changes in exposure to new environmental carcinogens, and changes in the criteria for the histopathologic diagnosis of lung cancer. The current study was designed to examine the incidence patterns of lung cancer by histologic type in Connecticut and to use this information to project the future trend of the disease in this population.

The time trend and age-period-cohort effects on incidence of adenocarcinoma of the stomach in Connecticut from 1955-1989

Background. Adenocarcinoma of the gastric cardia has been be increasing in Connecticut, and the risk factors responsible for the increasing incidence are unknown. This study examined the incidence pattern of adenocarcinoma of the gastric cardia and distal stomach in Connecticut during the past decades and identified components of birth cohort, period, and age as determinants of the observed time trends by regression modeling.

Malignant melanoma risk factors by anatomic site: A case‐control study and polychotomous logistic regression analysis

This population‐based case‐control study systematically examined reported malignant melanoma risk factors by anatomic site. Study subjects consisted of 548 invasive melanoma cases diagnosed in Connecticut during 1987–1989 and 494 randomly selected controls. Multivariate polychotomous logistic regression was used to determine whether risk factors differed across anatomic sites. Risk factors examined included demographic and pigmentary characteristics, sun exposure‐related factors, anatomic site‐specific sunburn, recreational water activity clothing habits and number of nevi. A pattern of site‐specificity was observed for sunburn. A history of sunburn at an anatomic site was specifically related to the development of malignant melanoma at that site more so than at other sites. This site‐specificity was consistent with a direct role for intense, intermittent sun exposure in the development of melanoma. Age and gender were the only risk factors that differed significantly in effect across anatomic sites. The age different was explained by differences in histologic subtype across sites. The gender difference could not be explained by sex differences in anatomic site‐specific sunburns or in recreational water activity clothing habits. Alternative explanations include sex differences in behavioral patterns of sun exposure that we did not measure and as yet unelucidated differences in susceptibility to melanoma according to sex and anatomic site.

Time trend and age-period-cohort effects on incidence of esophageal cancer in Connecticut, 1935–89

The purpose of this study was to examine the incidence pattern of esophageal eancer in Connecticut (USA) during the past decades, and to identify components of birth cohort, period, and age as determinants of the observed time trends by regression modelling. This study is based on all of the esophageal cancer cases reported to the Connecticut Tumor Registry between 1935 and 1989. A total of 6,310 incident cases were included. Results indicate that among males, the overall age-adjusted incidence rate of esophageal cancer increased after 1935 and peaked between 1955 and 1959. Since then, incidence rates have been relatively stable. Among females, the overall esophageal cancer rate has not changed markedly since 1935. Analysis by histologic type indicates that the incidence rate of squamous cell carcinoma has been declining in this population; adenocarcinoma, however, showed a continuous increase. A fivefold increase among males and a threefold increase among females were observed for adenocarcinoma of the esophagus between 1970 and 1989. If cancers of the esophagus and gastric cardia are considered together, the incidence rate of adenocarcinoma exceeds that of squamous cell carcinoma among males during 1985–89. The observed increasing trend for adenocarcinoma of the esophagus is mainly from cancers arising in the lower third of the esophagus and primarily among Whites, especially White males. The results from regression modeling indicate that both period and birth cohort may have contributed to the observed increasing trend, and adenocarcinoma of the esophagus is likely to increase continuously in this population in the coming years.

The increase of Hodgkin's disease incidence among young adults

Recent studies have indicated an increase in young adulthood Hodgkins disease incidence, particularly among females, since 1970. However, no studies have examined the long term trends and period‐cohort patterns of Hodgkins disease incidence.

Risk of tongue cancer associated with tobacco smoking and alcohol consumption: a case-control study

Recent studies indicate that cancer of the tongue is increasing rapidly among the younger population in many parts of the world. Few studies, however, have directly examined the risk factors for the disease. A case-control study was conducted in Beijing, China to investigate risk factors for tongue cancer. A total of 111 cases and 111 controls aged 20-80 years were included in this study. The results show that risk of tongue cancer is significantly elevated among ex-smokers (OR = 2.24, 95% CI = 1.09-4.62) and among current smokers (OR = 2.73, 95% CI = 1.26-5.91). The risk increases with increasing tobacco consumption, as reflected by both cigarette equivalents smoked per day and lifetime pack-years of tobacco smoking. Quitting smoking was associated with a reduction of the risk of tongue cancer. The numbers of cases in the study, however, is small, preventing further analyses during the years after quitting smoking. Overall, alcohol drinking was not found to be significantly associated with the risk of tongue cancer in this study (OR = 1.20, 95% CI = 0.58-2.50 for current drinkers). However, a marginally significant association was found for those who drank spirits at least 5 days a week (OR = 2.34, 95% CI = 0.90-6.06). A suggestion of effect modification for smoking and alcohol drinking was observed in this study.

Malignant melanoma incidence in Connecticut (United States): time trends and age-period-cohort modeling by anatomic site.

This study examined time trends and age-period-cohort patterns in the incidence of cutaneous malignant melanoma (CMM) by gender and anatomic site in Connecticut (United States) between 1950 and 1989, using data from the population-based Connecticut Tumor Registry. A total of 8,249 invasive CMM incident cases were included. Cases were grouped into melanomas of the head and neck, upper limb, lower limb, and trunk. Between 1950 and 1989, rates increased substantially for all sites. The largest relative increases occurred in melanoma of the upper limb for both males and females; the largest absolute increase occurred for melanoma of the trunk in males; and the smallest increase occurred in head and neck melanoma in females. Recent trends for time periods 1970–89 among birth cohorts 1930–69 indicated that the rate of increase of CMM is slowing substantially among males, but not among females. Nevertheless, continued overall increases in CMM incidence are likely in Connecticut in the 1990s in both genders, with a decrease in the male-female ratio. The age-period-cohort patterns were significantly different between the genders and among anatomic sites, suggesting different trends in carcinogenic exposures (mainly ultraviolet radiation from the sun) or etiologic distinctions between males and females and among the sites.

Interobserver agreement in a community skin cancer screening setting

To evaluate the appropriateness of screening as a preventive health tool, it is necessary to estimate its validity (or accuracy) and reliability (or reproducibility). Accuracy is determined by measures of sensitivity, specificity, and positive predictive value, whereas reliability reflects the consistency of results when the test is performed more than once on the same person under the same conditions. l The accuracy and reliability of skin cancer screening have not been examined extensively. A few studies have assessed positive predictive value by correlating histopathologic findings with screening diagnoses2-6; although one study addressed the reproducibility of the screening examination itself, it reported interobserver agreement between dermatologists and dermatology nurses.6 Our study examines interobserver agreement between dermatologists in a community skin cancer screening setting.