Fred Gilbert

Factors associated with mammographic pattern

Wolfes criteria were assigned to mammograms of 202 women without breast cancer. Parity decreased the frequency of P2 patterns but not DY. P1 and N1 patterns apparently increased at the expense of P2 patterns. For every birth, the probability that a P2 pattern changed to P1 or N1 was roughly 7 or 8%. This effect was not limited to the first pregnancy, but also held for additional pregnancies. Low body weight was associated with dysplasia and prominent duct patterns. Reported declines of radiographic density with increasing age and/or menopause were confirmed. Ethnic group was unrelated to parenchymal pattern.

Clinical report on long-term bone density after short-term EMF application

A 1984 study determined the effect of a 72 Hz pulsating electromagnetic field (PEMF) on bone density of the radii of post-menopausal (osteoporosis-prone) women, during and after treatment of 10 h daily for 12 weeks. Bone mineral densities of the treated radii increased significantly in the immediate area of the field during the exposure period and decreased during the following 36 weeks. Bone density determination of the radii of these women, remeasured after eight years, suggests no long-term changes. The bone density-enhancing effect of PEMFs should be further studied, alone and in combination with exercise and pharmacologic agents such as the bisphosphonates and hormones, as prophylaxis in the osteoporosis-prone postmenopausal woman and as a possible block to the demineralization effect of microgravity.

Factors associated with breast structure in breast cancer patients

The breast duct patterns and radiographic density, or dysplasia, of 104 breast cancer patients in Hawaii were examined by mammography. The proportions of the four types of breast structure were analyzed for possible relation with age, menopausal state, height, weight, and race. Multiple regression analysis indicated that menopausal state appears to be more important than age per se for the general change in breast structure. Low body weight, but not race, is associated with prominent duct patterns and dysplasia.

Wolfe's mammographic classification and breast cancer risk: the effect of misclassification on apparent risk ratios

The effect of misclassification of Wolfes mammographic classifications was investigated using data from two radiologists. If there are only two risk groups (high and low), the apparent relative risk expected from typical surveys would be around 2 or 3, even if the true relative risk is very high. If each of Wolfes four classes has its own risk, the difference between N1 and P1, on the one hand, and P2 and DY on the other, would be almost lost due to misclassification. Published surveys in which the observed relative risks for the high-risk group (P2 and DY) are low are not inconsistent with Wolfes original finding of a high relative risk: misclassification can greatly distort estimates of relative risks. If misclassification can be managed by restricting uncertain mammograms to one class (or by removing them from the study altogether), the bias can be greatly reduced.

Age at first pregnancy in relation to age at menarche and year of birth in Caucasian, Japanese, Chinese and part-Hawaiian women living in Hawaii

A multiple regression analysis was undertaken to examine the relationship between age at first pregnancy and recollected age at menarche and sociological variables in Caucasian, Japanese, Chinese and part-Hawaiian parous women living in Hawaii. The analysis was conducted using the medical history records of 1198 Caucasian, 1770 Japanese, 453 Chinese and 578 part-Hawaiian women. Age at first pregnancy varied significantly among ethnic groups. Initial results showed an apparent heterogeneity among ethnic groups in the effect of age at menarche on age at first pregnancy. Once appropriate controls for the linear and non-linear effects of year of birth were made, the effects of age at menarche on age at first pregnancy no longer varied significantly among ethnic groups. The observed secular trends in age at first pregnancy have varied widely among the four ethnic groups studied and appear unrelated to genetic background.

Recalled characteristics of menstruation in relation to reproductive history among Caucasian, Japanese and Chinese women living in Hawaii

Characteristics of menstruation and reproductive history were studied in 2331 Caucasian, 4097 Japanese and 1003 Chinese women living in Hawaii and born between 1900 and 1940. Irregular periods, heavy flow and menses lasting more than five days were reported significantly more often in Caucasians than in the other two groups. Canonical correlation and multiple-regression procedures revealed that parity, recalled age at menarche and year of birth were significantly associated to the menstrual descriptions reported, in complex ways, distinctive in each ethnic group. Some similarities in the relationship of reproductive history variables with particular menstruation characteristics were found in the Caucasian and Japanese groups. For example, increased parity was associated with increased menstrual bleeding in both Caucasians and Japanese, and later age at menarche was significantly correlated with irregular menses in these two groups.

Estimating the sensitivity of breast cancer screening - Experience with the Honolulu BCDDP data

SummaryThe ‘capture-recapture’ models for estimating breast cancer screening sensitivity can be generalized to include factors that affect sensitivity such as cancer size. Including such factors can help reduce the covariance between mammographic and physical exam sensitivity, which will improve the estimates. One model relating sensitivity to cancer length is presented and tested using data from the Honolulu Breast Cancer Detection Demonstration Project (BCDDP). The model predicts sensitivity fairly well for large breast cancers, but underestimates sensitivity for small cancers. Using both mammography and physical examination, the total screening sensitivity is estimated as 0.91±0.03 for cancers longer than 12 mm (for the second through fifth screenings for Honolulu and Tucson screening data combined). Limited data suggest similar screening sensitivities for Orientals and Caucasians in Hawaii. Shortcomings of the BCDDP data include inaccurate measurements of cancer length. Suggestions to improve data for future work are given.

Racial variation in diabetes mellitus in Japanese and Caucasians living in Hawaii

Comparisons were made between diabetic and control groups in Japanese and Caucasians living in Honolulu, Hawaii. The study was performed on the multiphasic screening records of 109 diagnosed diabetics and 173 healthy controls in Japanese, and 69 diagnosed diabetics and 326 healthy controls in Caucasians. Discriminant function analysis was employed with relevant anthropometric, medical, and biochemical variables. The common set of significant discriminant variables were: diabetic sib, a history of high blood pressure, systolic blood pressure, urine sugar, glucose over 190 mg%, and serum glutamic-oxalacetic transaminase, with age and sex effects fitted. The data suggested that heterogeneity exists between the two racial groups in the relationships of some of these variables with the disease.