The relationship between obesity and breast cancer recurrence

Researchers were interested in assessing the relationship between obesity and breast cancer recurrence and fatality in postmenopausal African-American and Caucasian women with primary breast cancer. Data was collected on women with primary breast cancer and included the following variables:
● Age
● Age at diagnosis of breast cancer
● Weight
● Height
● Data of diagnosis of breast cancer
● Menopausal status
● Diagnosis and coding of tumor (histopathology and topography)
● Stage of tumor
● Size of tumor
● Number of positive lymph nodes
● Estrogen receptor analysis
● Progesterone receptor analysis
● Site of distant metastasis
● First course of treatment (surgery, radiation, chemotherapy)
● Additional treatment
● Five-year recurrence and survival rates
Recurrence and survival status were determined by reviewing the cancer registry follow-up data and medical record information across the multiple healthcare sites involved in this study. The cancer registries were accredited by the American College of Surgeons and used active follow-up on all cancer patients. Postmenopausal status was determined as subjects older than 55 years. In those subjects younger than age 55, determination was made by consulting the cancer registry data, the medical record, and physician’s office records. Premenopausal patients and patients whose menopausal status could not be determined from the data were excluded from the study. Body mass index (BMI) was based on height and weight collected from the medical record or cancer registry at the date of diagnosis only. Values greater than 27 were considered to indicate obesity. The effect of weight changes during the follow-up period was not evaluated.

read the attached document and answer the following questions.

1. How was obesity determined in this group of patients?
2. Why is it important to collect the other variables when studying the relationship between obesity and breast cancer recurrence?
3. Postmenopausal status was determined as subjects older than 55 years. What may be a better way to determine whether the women in this study were postmenopausal?
4. What type of study design is this? If it was found that obesity and breast cancer recurrence were related what type of study could be conducted to test whether changes in diet may make a difference in the recurrence of breast cancer in women who have had primary breast cancer?
5. This study did not examine pre-menopausal women. It did not look at other races besides African American. Is this a limitation? Why or why not?