Zhihong Gong

Survival in Population-based Pancreatic Cancer Patients: San Francisco Bay Area, 1995–1999

Patient vital status generally is passively obtained by cancer registries, and no previous population-based studies have used extensive active follow-up to compute a more accurate overall survival rate for pancreatic cancer. Therefore, the authors used multiple active and passive follow-up methods to determine vital status and date of death for 1,954 pancreatic cancer patients diagnosed from 1995 to 1999 in a large population-based study in the San Francisco Bay Area, California. Survival rates were estimated by using Kaplan-Meier methods. Hazard ratios and 95% confidence intervals were estimated by using multivariable Cox proportional-hazards models. Vital status was confirmed for >99% of 1,954 patients. The overall 5-year survival rate was 1.3% and was greater in patients who were younger and who had localized disease, well-differentiated tumors, and surgical resection. Shorter survival was associated with older age at diagnosis, male sex, distant/metastatic disease, and poorly differentiated tumors. Longer survival was observed for Asian/Pacific Islanders compared with non-Hispanic whites and for any active treatment regardless of tumor stage. With an almost complete follow-up, the authors observed a low overall 5-year survival rate. Although the results provide further evidence of poor survival among patients with pancreatic cancer, the data also suggest that within-stage-of-disease patients survived somewhat longer with therapy.

Intake of fatty acids and antioxidants and pancreatic cancer in a large population-based case-control study in the San Francisco Bay Area

There are no well‐established modifiable risk factors for pancreatic cancer except smoking. Some dietary factors have been associated with pancreatic cancer risk and require further study. We examined the associations among intake of specific fatty acids and antioxidants and risk of pancreatic cancer in a large population‐based case‐control study in the San Francisco Bay Area. Unconditional logistic regression models were used to compute odds ratios (ORs) and 95% confidence intervals (CI) as estimates of relative risk. Positive associations were observed for high levels of the 8 individual saturated fatty acids (4th vs. 1st quartile: ORs ranged from 1.6 to 2.6; all ptrend < 0.01), monounsaturated palmitoleic and oleic fatty acids [OR = 1.6 (95% CI: 1.2–2.1) and 1.4 (95% CI: 1.1–1.9); both ptrend < 0.01], and polyunsaturated linolenic acid [OR = 1.5 (95% CI: 1.1–2.0); ptrend = 0.02]. Inverse associations were observed for high levels of gadolic acid [4th vs. 1st quartile: OR = 0.68 (95% CI: 0.50–0.92); ptrend = 0.007] and omega‐3 fatty acids [≥0.85 g/day vs. 1st quartile: OR = 0.47 (95% CI: 0.25–0.90)]. An inverse association was also observed for high total intake of vitamin C [4th vs. 1st quartile: OR = 0.69 (95% CI: 0.51–0.94); ptrend = 0.004] and of vitamin E [OR = 0.67 (95% CI: 0.49–0.92); ptrend = 0.01]. Although similar decreased risks were also observed for high supplemental intake of these 2 vitamins (both ptrend < 0.01), no association was observed for intake from food alone. These results support the hypotheses that a high intake of saturated and certain monounsaturated fatty acids may increase the risk of pancreatic cancer, whereas greater intake of omega‐3 fatty acids, vitamins C and E may reduce the risk.

Dietary Patterns and Risk of Pancreatic Cancer in a Large Population-Based Case-Control Study in the San Francisco Bay Area

Pancreatic cancer is highly lethal, and identifying modifiable risk factors could have substantial public health impact. In this population-based case-control study (532 cases, 1701 controls), we used principal component analysis and multivariable unconditional logistic regression models to examine whether a particular dietary pattern was associated with risk of pancreatic cancer, adjusting for other known risk factors. A prudent dietary pattern, characterized by greater intake of vegetables, fruit, fish, poultry, whole grains, and low-fat dairy, was associated with an approximate 50% reduction in pancreatic cancer risk among men [odds ratio (OR) = 0.51, 95% confidence intervals (CI) = 0.31–0.84, P trend = 0.001] and women (OR = 0.51, 95% CI = 0.29–0.90, P trend = 0.04). A Western dietary pattern, characterized by higher intake of red and processed meats, potato chips, sugary beverages, sweets, high fat dairy, eggs, and refined grains, was associated with a 2.4-fold increased risk of pancreatic cancer among men (95% CI = 1.3–4.2, P trend = 0.008) but was not associated with risk among women. Among men, those in the upper quintiles of the Western diet and lower quintiles of the prudent diet had a threefold increased risk. Consistent with what has been recommended for several other chronic diseases, consuming a diet rich in plant-based foods, whole grains, and white meat, might reduce risk of pancreatic cancer.

Urinary Iodine and Goiter Prevalence in Belarus: Experience of the Belarus–American Cohort Study of Thyroid Cancer and Other Thyroid Diseases Following the Chornobyl Nuclear Accident

BACKGROUND Because iodine deficiency can influence background rates of thyroid disease or modify radiation dose-response relationships, we compiled descriptive data on iodine status among participants in a Belarusian-American screening study who were exposed in childhood to radioiodine fallout from the Chornobyl nuclear accident. We have used the data from two consecutive screening cycles to examine whether indicators of iodine status changed before and after documented government initiatives to improve iodine intake. METHODS Urinary iodine concentrations in spot samples and prevalence of diffuse goiter by palpation were assessed in 11,676 exposed subjects who were 18 years or younger at the time of the accident on April 26, 1986, and were screened beginning 11 years later in connection with the Belarus-American Thyroid Study. Data for the first ( January 1997-March 2001) and second (April 2001-December 2004) screening cycles, which largely correspond to time periods before and after official iodination efforts in 2000/2001, were compared for the cohort overall as well as by oblast of residence (i.e., state) and type of residency (urban/rural). RESULTS Median urine iodine levels among cohort members increased significantly in the later period (111.5 mg/L) compared to the earlier (65.3 mg/L), with the cycle 2 level in the range defined as adequate iodine intake by the World Health Organization. During the same period, a significant decline in diffuse goiter prevalence was also observed. In both cycles, urinary iodine levels were lower in rural than in urban residents. Urinary iodine levels, but not rates of goiter, varied by oblast of residence. In both periods, adjusted median urine iodine concentrations were similar in Gomel and Minsk oblasts, where *89% of cohort members resided, and were lowest in Mogilev oblast. Yet Mogilev oblast and rural areas showed the most marked increases over time. CONCLUSIONS Trends in urinary iodine concentrations and prevalence of diffuse goiter by palpation suggest that iodination efforts in Belarus were successful, with benefits extending to the most iodine-deficient populations. Iodine status should be considered when evaluating thyroid disease risk in radioiodine-exposed populations since it can change over time and may influence rates of disease and, possibly, dose-response relationships

Intake of Vitamins D and A and Calcium and Risk of Non-Hodgkin Lymphoma: San Francisco Bay Area Population-Based Case-Control Study

Several nutrients identified as potentially cancer protective have been inconsistently associated with non-Hodgkin lymphoma (NHL) risk. Dietary history data, including use of vitamin supplements, were collected using a semiquantitative food frequency questionnaire administered during in-person interviews with 4,133 participants (2,052 cases, 2,081 controls) in a San Francisco Bay Area population-based case-control study. Data were used to determine the association of intake levels of vitamins D and A and calcium with risk of NHL and NHL subtypes. Odds ratios (OR) and 95% confidence intervals (CI) were computed as estimates of relative risk using adjusted unconditional logistic regression. Increasing vitamin D intake from food and supplements was positively associated with NHL risk in men (5th quintile: OR = 1.6, 95% CI = 1.0–2.4, P trend = 0.07) and with diffuse large B-cell lymphoma (DLBCL) in women and men (5th quintile: OR = 1.6, 95% CI = 1.0–2.5, P trend = 0.02); that was largely due to the effect in men (P trend = 0.03). These results do not support a strong role for vitamin D intake with NHL risk, with the exception of a potential association for DLBCL risk in men. Our results should be interpreted conservatively until further investigation in larger pooled studies can be conducted to better assess the role of vitamin D intake in lymphomagenesis.

Analysis of thyroid malignant pathological findings identified during three rounds of screening (1997-2008) of a Belarusian cohort of children and adolescents exposed to radioiodines after the Chernobyl accident

Recent studies of children and adolescents who were exposed to radioactive iodine‐131 (I‐131) after the 1986 Chernobyl nuclear accident in Ukraine exhibited a significant dose‐related increase in the risk of thyroid cancer, but the association of radiation doses with tumor histologic and morphologic features is not clear.