Prospective study of pulmonary function and lung cancer

The role of pulmonary function as an independent predictor of lung cancer risk was studied in a community-based cohort of 6,317 Japanese-American men who were aged 45 to 68 at the time of examination. After a follow-up period of about 22 yr, 172 incident cases of lung cancer were identified. The percentage of the predicted FEV1 was inversely related to lung cancer (p value for trend = 0.01) after adjustment for age and cigarette smoking history. The subjects in the lowest quartile of pulmonary function (% predicted FEV1 less than 84.5) had a relative risk of 2.1 (95% confidence interval = 1.3 to 3.5) for lung cancer compared with subjects in the highest quartile (% predicted FEV1 = 103.5+). For the 84 cases with a squamous or small cell histologic type of lung cancer, the subjects in the lowest quartile had a relative risk of 2.5 (95% Cl = 1.2 to 5.6) compared with subjects in the highest quartile of pulmonary function. For the 84 patients with lung cancer whose tumors were located within 4 cm of the pulmonary hilum, the subjects in the lowest quartile had a relative risk of 4.0 (95% Cl = 1.7 to 9.7). The results suggest that impaired pulmonary function in a community-based population is a predictor of lung cancer.     

Dietary fat and the risk of colorectal cancer

The relationship between the intake of dietary fat and subsequent colorectal cancer during a 15-year follow-up was investigated in 7074 men of Japanese ancestry, 45 to 68 years old and living in Hawaii. Data on fat intake were obtained by 24-hr recall records at base-line examination. We found a statistically significant, negative association between colon cancer and the intake of saturated fat, whether assessed on the basis of g per day or as a percentage of the caloric intake. There was a similar association with total fat intake when expressed in terms of percentage of total calories. The strongest negative relationship was found in cancer of the right colon. In contrast, rectal cancer showed a weakly positive relationship to the intake of saturated fat when assessed on the basis of percentage of caloric intake.     

Body mass index as a predictor of cancer in men

In this prospective study 8,006 Japanese men, age 45-68 years, were examined between 1965 and 1968. Their height and weight were measured and they were asked for their weight at age 25. After a surveillance period of almost 15 years, 646 incident cases of the following cancers were identified: 104 stomach, 101 colon, 101 lung, 96 prostate, 63 rectum, and 181 cancers of other sites. Body mass index (BMI = weight/height2) at time of examination and weight gain since age 25 were positively associated with an increased risk for colon cancer in subjects age 55 or older at the time of examination. No other cancer had a significant positive association with either BMI at the time of examination or with weight gain since age 25. In contrast, a low BMI at examination and weight loss since age 25 were associated with an increased risk for stomach cancer, whereas only weight loss since age 25 was associated with an increased risk for lung cancer. These two cancers accounted for the overall significant association of weight loss with total cancer incidence.     

A prospective comparison of prostate cancer at autopsy and as a clinical event: the Hawaii Japanese experience.

Prostate cancer was diagnosed in life among 274 of 8006 (3.6%) members of a cohort of Japanese men in Hawaii between 1965 and 1990. Only 55 (20%) of the 274 diagnosed cases died with prostate cancer, and they accounted for only 2% of the 2893 deaths that occurred among the men during this period. None of the 61 men whose tumor was found incidentally to a transurethral resection died as a result of this cancer, while it was the cause of death of 9 of 106 (8%) men with clinical cancer localized to the prostate. Forty-six of the 107 (43%) men with more extensive disease at the time of diagnosis died from prostate cancer. Step sectioning of the prostate identified prostate cancer in 80 of 293 (27%) autopsied Hawaii Japanese men who died after 50 years of age, reaching a frequency of 63% (10 of 16) among men over 80 years of age. The volume of 48 (60%) of these cancers was less than 150 mm3. These small tumors would probably not have been discovered in a screening program. Tumors larger than 1000 mm3 would probably be discovered using modern diagnostic procedures but were found in only 13 (4.4%) of the autopsied men. It is likely that a screening program to detect and treat such large, unsuspected tumors in this population would have had little impact upon the already low proportion of deaths due to prostate cancer among these Japanese men.     

A prospective study of the attributable risk of cancer due to cigarette smoking.

BACKGROUND. The goals of this study were to measure the impact of cigarette smoking on cancer incidence and to determine the attributable risk of cancer due to smoking. METHODS. A cigarette smoking history was obtained from 8006 Japanese-American men examined from 1965 through 1968. After 22 years, 1389 incident cases of cancer were identified. There were 212 men with lung cancer; 202 with oral, esophageal, laryngeal, pancreatic, renal, ureteral, or bladder (oral-bladder) cancer; and 975 with cancer at other sites. RESULTS. Current smokers at time of examination had a higher incidence than nonsmokers for each of the three cancer site categories. Eighty-five percent of lung cancer cases diagnosed among current and never smokers can be attributed to cigarette smoking. The attributable risks were 46%, 16%, and 29%, respectively, for oral-bladder cancers, other cancers, and all cancers combined. In turn, the corresponding attributable risks were 60%, 26%, 13%, and 21% in comparing current smokers with past smokers. CONCLUSIONS. Current smokers can greatly reduce their risk of cancer, especially lung cancer, if they quit smoking.     

Ciliated gastric cells among Japanese living in Hawaii

A total of 129 consecutive gastrectomy specimens from Japanese (99), Philippinos (11), Hawaiians (8), Koreans (5), Chinese (4) and Caucasians born in Hawaii (2) were examined under high-power light microscopy (1000 x) for the presence of ciliated gastric cells. Fifty-two of the 129 gastrectomy specimens (40.3%) contained ciliated cells. Ciliated cells were found in the basal segments of antral glands (usually cystically dilated) whose superficial segments had undergone intestinal metaplasia. The presence of ciliated cells in the gastric mucosa was influenced by the age of the patient and by the degree of intestinal metaplasia: the older the patient, the greater the degree of intestinal metaplasia and the greater the frequency of specimens with ciliated cells. The presence of ciliated cells was also influenced by the type of lesion in the specimen. Although the highest frequency (47.2%) was found in stomachs removed for adenocarcinoma, a substantial number of stomachs removed for gastric ulcer also showed that change (36%). The data suggest that increasing age and advanced atrophic gastritis, especially of the antrum, provide the necessary conditions that lead to the development of cilia, not only in Japanese subjects, but in other Hawaiian ethnic groups as well.     

The effects of non-response in a prospective study of cancer: 15-year follow-up

Out of 11,136 Japanese men identified on the island of Oahu, Hawaii in 1965 by the Honolulu Heart Program, 8006 responded to a mailed questionnaire and were examined. Some 1871 responded only to the mailed questionnaire, and 1259 did not respond at all. After 15 years of follow-up, the examined men had significantly lower risk of death from all causes and death from cancer. Minor differences were also noted between the two groups in the risk of cancer of the lung, stomach, colon, and rectum. However, the examined men had a significantly higher risk of prostate cancer. In general, the strength of these non-response effects was mainly due to risk differences in the first five years of the 15-year follow-up period. The relative risk (RR) of each of the seven endpoint events tended towards 1.0 as each of the three successive five-year follow-up intervals were considered. An exception to this was the prostate cancer incidence RR which favoured the unexamined men throughout the entire 15 years, but significantly so only in the last five-year follow-up interval. When the 8006 examined and 1871 unexamined men who responded to the mailed questionnaire were evaluated with respect to the association of cigarette smoking with lung cancer incidence, the RR for smokers was 9.77 for the examined men, and 6.73 for the unexamined men. Since these RRs are not significantly different, there should be little bias in RR estimates of cigarette smoking for lung cancer if the observation was limited to only the examined men. With regard to the association of body mass index (BMI) with colon cancer in older men, the RRs for men in the highest BMI quintile were quite comparable, at 1.37 for the examined group and 1.60 for the unexamined men. We conclude that although some non-response effects on cancer incidence exist in this cohort, they do not appear to be serious enough to have changed conclusions drawn about risk relationships.     

Cancer incidence in Hawaiian Japanese: migrants from Okinawa compared with those from other prefectures.

Japanese men in Hawaii whose ancestral roots were in Okinawa were compared to Japanese migrants from all other prefectures. The Okinawan migrants have acquired fewer cancers than men from other prefectures (P = 0.12). No one primary site accounts for this difference. Stomach cancer rates showed the largest difference between the two migrant groups. This replicates the experience of Okinawans and non-Okinawans in Japan itself. Lymphosarcoma mortality rates are much higher in Okinawa than in all Japan, but this difference is not reproduced in Hawaiian migrants. This could be explained by a post migrational decrease in HTLV-I-related acute T-cell lymphoma/leukemia. Cancer of the mouth, pharynx and esophagus has decreased in all Japanese migrants, but the decrease is much greater among Okinawan migrants, suggesting they have escaped exposure to risk factors peculiar to the Okinawan environment. Colon cancer is more common in migrant Japanese than in U.S. whites. The dramatic increase in the frequency of this tumor affects Okinawan and non-Okinawan migrants to an equal degree.