Prior studies have observed a link between night shift work and increased risk of breast cancer. Melatonin, a hormone related to circadian rhythm, has been proposed to lower breast cancer risk by inhibiting cell proliferation. The disruption of peak melatonin that occurs during night shift work could explain the increase in risk observed. Several studies have assessed whether higher melatonin levels are associated with decreased breast cancer risk, but results have been conflicting. We examined the relationship between urinary melatonin levels and breast cancer risk in a nested case-control study conducted within the Women’s Health Initiative Observational Study. First morning urine samples collected at baseline were assayed for melatonin levels in 258 women diagnosed with invasive breast cancer and 515 matched controls from three enrollment sites. Using conditional logistic regression to adjust for matching factors and established risk factors, results indicate no association between urinary melatonin levels and breast cancer risk. The mean creatinine adjusted melatonin levels for cases and controls were 16.30 ng/mg and 16.05 ng/mg, respectively. Compared to the lowest quartile of creatinine adjusted melatonin, the odds of breast cancer did not vary by quartile of creatinine adjusted melatonin, adjusted for known breast cancer risk factors: second quartile 0.84 (95% CI 0.52-1.38), third quartile 1.05 (95% CI 0.65-1.72) and fourth quartile 1.09 (95% CI 0.66-1.81). This study does not suggest that melatonin is protective against breast cancer and suggests that reasons other than melatonin suppression may explain the increased risk of breast cancer seen in night shift workers.

Endometrial cancer is the most common female reproductive cancer in the United States. Most known risk factors for endometrial cancer are either genetic or related to exposure to estrogens; less is known about risk due to environmental exposures. While several studies have examined the relationship between perineal powder use and ovarian cancer risk, only one study has addressed the relationship with endometrial cancer risk. The Women's Health Initiative Observational Study, a prospective cohort study of 93,676 United States postmenopausal women from 1993-2005, measured perineal powder use at baseline via self-report. Cases of endometrial cancer were self-reported and confirmed by both local and central physician adjudicators. Cox proportional hazards regression was used to examine the association between perineal powder use and endometrial cancer, adjusting for known risk factors. Of the 48,912 women in our analysis, 25,181 (52%) reported ever use of perineal powders. There were 452 incident cases of endometrial cancer diagnosed during 366,872 person-years of follow-up. Ever use of perineal powder was not significantly associated with increased risk of endometrial cancer (hazard ratio 1.05, 95% confidence interval 0.87-1.27). However, use of any perineal powder for 20 or more years was associated with a 30% increase in risk (hazard ratio 1.30, 95% CI 1.01-1.67) compared to never users. Use of powder on both a diaphragm and the perineal area was associated with a 39% increase in risk (hazard ratio 1.39, 95% CI 1.00-1.93). Cessation of perineal powder use, particularly on a diaphragm, may help reduce risk of endometrial cancer.

No description available.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 4 uppsatser.

This dissertation’s three studies investigated the short and long-term relationships of bone-related nutrient intakes with bone mineral density (BMD) in postmenopausal women. This dissertation compared the equivalency of dietary intakes assessed by eight days of diet records (DR) and the Arizona Food Frequency Questionnaire (AFFQ) at one year. It also determined the association of one year (DR) and the average of four-year (AFFQ) dietary intakes with cross-sectional BMD. The dietary intake associations with BMD were further investigated by hormone therapy (HT). Participant’s BMD was measured at the lumbar spine (L2-L4), femur trochanter, femur neck, Ward's triangle and total body using dual energy X-ray absorptiometry. Separate multiple linear regression analysis (p≤0.05), controlled for various covariates, were used to examine the associations between dietary intakes and regional and total body BMD. In study number one (n=266), significant correlations (r=0.30-0.70, p≤0.05) between dietary assessment methods were found with all dietary intake variables. Iron, magnesium, zinc, dietary calcium, phosphorous, potassium, total calcium, and fiber intakes were positively associated with BMD at three or more of the same bone sites regardless of the dietary assessment method at one year. In study number two (n=266), femur trochanter, lumbar spine, and total body BMD had mostly significant inverse associations with dietary polyunsaturated fatty acid (PUFA) intake at one year. In the HT group (n=136), inverse associations with dietary PUFA intake were seen in the spine and total body BMD. In study number three (n=130), average dietary intake of selected bone-related nutrients, were significantly inversely associated with lumbar spine BMD and total body BMD at year four. In the HT group (n=92), inverse associations with dietary PUFA intake were seen in the spine and total body BMD. The DR and AFFQ are acceptable dietary tools used to determine the associations of particular nutrients and BMD sites in healthy postmenopausal women at one year. At one and four year, dietary PUFA intakes had mostly inverse associations with lumbar spine and total body BMD. When categorized by HT use the associations remained significant only in the HT groups, suggesting that HT may influence dietary intake associations with BMD.

No description available.

Striking differences exist between countries in the incidence of breast cancer, with rates higher in the West than in Asian countries. The causes of these differences are unknown, but because incidence rates change in migrants, they are thought to be due to lifestyle rather than genetic differences. The objective of this thesis was to compare established breast cancer risk factors, physical activity, and diet in three groups of postmenopausal women at substantially different risks of developing breast cancer – Caucasians (N = 413), Chinese born in the West or who migrated to the West before age 21 (N = 216), and recent Chinese migrants, 99% of whom coming from urban China (N = 421). In this cross-sectional study, information on risk factors and diet were collected by telephone, and physical activity and anthropometric data were obtained at a home visit. Compared to Caucasians, recent Chinese migrants weighed on average 14 kg less, were 6 cm shorter, had menarche a year later, were more often parous, and less often had a family history of breast cancer or a benign breast biopsy. Estimating 5-year absolute breast cancer risks using the Gail Model showed that risk estimates in Caucasians would be reduced by only 11% if they had the risk factor profile of recent Chinese migrants for the variables in the Gail Model. Compared to Caucasians, recent Chinese migrants had lower average total physical activity over lifetime, and also spent less time on moderate- and vigorous-intensity activity. Compared to Caucasians, recent Chinese migrants consumed per day on average 175 fewer calories, 6 more grams of energy-adjusted protein, 16 more grams of energy-adjusted carbohydrates, and 5 fewer grams of energy-adjusted fat. Also, recent Chinese migrants consumed higher amounts of grains, fruits, vegetables, fish, and soy products, and lower amounts of alcohol, meat, dairy products, and sweets than Caucasians. Western born Chinese and early Chinese migrants had values intermediate between the other two groups for most of the variables. These results suggest that in addition to the established risk factors, some dietary factors may also contribute to the lower breast cancer risk in urban Chinese women.

Striking differences exist between countries in the incidence of breast cancer, with rates higher in the West than in Asian countries. The causes of these differences are unknown, but because incidence rates change in migrants, they are thought to be due to lifestyle rather than genetic differences. The objective of this thesis was to compare established breast cancer risk factors, physical activity, and diet in three groups of postmenopausal women at substantially different risks of developing breast cancer – Caucasians (N = 413), Chinese born in the West or who migrated to the West before age 21 (N = 216), and recent Chinese migrants, 99% of whom coming from urban China (N = 421). In this cross-sectional study, information on risk factors and diet were collected by telephone, and physical activity and anthropometric data were obtained at a home visit. Compared to Caucasians, recent Chinese migrants weighed on average 14 kg less, were 6 cm shorter, had menarche a year later, were more often parous, and less often had a family history of breast cancer or a benign breast biopsy. Estimating 5-year absolute breast cancer risks using the Gail Model showed that risk estimates in Caucasians would be reduced by only 11% if they had the risk factor profile of recent Chinese migrants for the variables in the Gail Model. Compared to Caucasians, recent Chinese migrants had lower average total physical activity over lifetime, and also spent less time on moderate- and vigorous-intensity activity. Compared to Caucasians, recent Chinese migrants consumed per day on average 175 fewer calories, 6 more grams of energy-adjusted protein, 16 more grams of energy-adjusted carbohydrates, and 5 fewer grams of energy-adjusted fat. Also, recent Chinese migrants consumed higher amounts of grains, fruits, vegetables, fish, and soy products, and lower amounts of alcohol, meat, dairy products, and sweets than Caucasians. Western born Chinese and early Chinese migrants had values intermediate between the other two groups for most of the variables. These results suggest that in addition to the established risk factors, some dietary factors may also contribute to the lower breast cancer risk in urban Chinese women.

Purpose: To evaluate the course of recovery in fall-risk and functional status over the first year following a distal radius fracture (DRF), and evaluate differences in fall and fracture risk factors in women over the age of 50 years with a DRF compared to their non-fractured peers. Methods: Two cohorts of participants volunteered in two sub-studies of the thesis. The first was seventy-eight women recruited from a DRF Clinic within the first week after their fracture, and followed up in concert with standard clinic appointments at week three, nine, 12, 26, and 52 post-fracture. The second cohort consisted of women aged 50 years or older, with and without a recent distal radius fracture, being at least 6 months post-DRF, but no more than 2 years post-fracture. Seventy-seven women age 50-78 with (Fx, n = 32) and without (NFx = 45) a history of DRF were assessed on two occasions within 4 weeks apart using a battery of fall and fracture risk tools, including balance, mobility, gait speed, fracture risk assessment, as well as bone quality assessment using peripheral quantitative computer tomography (pQCT) and dual x-ray absorptiometry (DXA). Results: Fall-risk status (strength, balance, mobility) gradually improved over the first year post-fracture, with balance confidence remaining high even immediately post-fracture. In the second study, women with a recent DRF, compared to women without, demonstrated higher fall and fracture risk. Women with a recent DRF had lower bone and muscle strength in both the upper and lower extremities compared to the non-fractured controls, with no differences in DXA derived aBMD at the femoral neck or spine. Significance of findings: The results of these studies will help clinicians understand the normal course of functional recovery post-fracture, and assist in determining appropriate fall risk assessment and interventions for post-menopausal women at risk of fragility fracture. Results demonstrate the importance of studying women at risk of DRF as an important first indicator of bone fragility and risk of future fracture. These findings also strengthen the notion that DXA alone may not be the best predictor for fracture risk.

Osteoporosis remains a major health issue worldwide. Although it has been associated with Caucasian women in the United States, attention is being drawn to other ethnicities. The National Institutes of Health (NIH) are concerned that people perceive osteoporosis to only affect Caucasian women, given that African-American (AA) women have higher bone mineral density and lower postmenopausal bone loss. This perception ignores observations that AA women are at significant risk of developing osteoporosis. As such, there is considerable delay in the prevention and treatment of osteoporosis among AA women. This cross-sectional study's design primary purpose was to describe postmenopausal AA women's knowledge, beliefs and behaviors concerning osteoporosis. Secondary to this purpose, was exploration of correlations between the Health Belief Model (HBM) theoretical constructs with osteoporosis preventive behavior, especially calcium intake and physical exercise. One hundred and fifty three postmenopausal AA women completed a questionnaire containing 1) the Osteoporosis Knowledge Test (OKT), 2) the Osteoporosis Health Belief Scale (OHBS), 3) the Osteoporosis Self-Efficacy Scale (OSES), 4) the Osteoporosis Attitude Knowledge Test (OAKT) and 5) the Osteoporosis Preventing Behaviors Survey (OPBS). The data were analyzed in SPSS version 21.0. The results of the study varied. Women in the study had greater knowledge about osteoporosis overall; they had less knowledge about preventing osteoporosis with exercise. They regularly used diet to prevent osteoporosis and reported recurrent physical activity. Participants had a general knowledge of osteoporosis but they experienced a moderate number of barriers that limited exercise. Few barriers for calcium intake were reported. Correlational analysis between age, number of months post-menopause, and education and the dependent variables (osteoporosis knowledge, beliefs, attitudes, and barriers to engaging in bone health promotion activities) revealed significant correlations. Age and number of years post menopause were significantly negatively correlated with use of physical activity to prevent osteoporosis. As women aged, they engaged in less osteoporosis prevention using exercise and as the number of months post menopause increased, the exercise behaviors associated with osteoporosis prevention decreased. This is an indication that women at this age have to be educated on the importance of exercising at this stage in their life.