Sheri J. Hartman

Predictive Validity of the Expanded Susceptibility to Smoke Index

OBJECTIVES The susceptibility to smoking index can be improved as it only identifies one third of future adult smokers. Adding curiosity to this index may increase the identification of future smokers and improve the identification of effective prevention messages. METHODS Analyses used data from the California Longitudinal Study of Smoking Transitions in Youth, for whom tobacco use behaviors, attitudes, and beliefs were assessed at 3 time points from age 12 through early adulthood. Logistic regressions were used to evaluate whether baseline curiosity about smoking was predictive of smoking during the 6-year follow-up period and whether curiosity about smoking provided evidence of incremental validity over existing measures of susceptibility to smoking. RESULTS Compared to those who were classified as definitely not curious about smoking, teens who were classified as probably not curious (OR adj = 1.90, 95% CI = 1.28-2.81) and those classified as definitely curious (OR adj = 2.38, 95% CI= 1.49-3.79) had an increase in the odds of becoming a young adult smoker. Adding curiosity to the original susceptibility to smoking index increased the sensitivity of the enhanced susceptibility index to 78.9% compared to 62.2% identified by the original susceptibility index. However, a loss of specificity meant there was no improvement in the positive predictive value. CONCLUSIONS The enhanced susceptibility index significantly improves identification of teens at risk for becoming young adult smokers. Thus, this enhanced index is preferred for identifying and testing potentially effective prevention messages.

Intermittent Fasting and Human Metabolic Health

Periods of voluntary abstinence from food and drink (i.e., intermittent fasting) has been practiced since earliest antiquity by peoples around the globe. Books on ethnology and religion describe a remarkable variety of fasting forms and practices.1 Renewed interest in fasting regimens is evidenced by a plethora of popular press publications and diet recommendations. For example, in 2013, Mosley and Spencer published a best-selling book titled “The Fast Diet,” which touts the benefits of restricting energy intake severely for two days a week while eating normally the rest of the week.2 Dozens of books promote various fasting dietary patterns and the web offers hundreds of fasting-related sites. However, scientific evidence for the health benefits of intermittent fasting in humans is often extrapolated from animal studies, based on observational data on religious fasting (particularly Ramadan), or derived from experimental studies with modest sample sizes. The overall objective of this paper is to provide an overview of intermittent fasting regimens (Table 1) and summarize the evidence on the health benefits of intermittent fasting with a focus on human intervention studies. Because much of the data on intermittent fasting is from research in animal models, we briefly summarize key rodent studies and reviews. Health outcomes of interest are changes in weight and metabolic parameters associated with type 2 diabetes, cardiovascular disease, and cancer. We also present an overview of the major mechanisms hypothesized to link fasting regimens with human health: (1) circadian biology, (2) the gastrointestinal microbiota, and (3) modifiable lifestyle behaviors such as diet, activity, and sleep. Finally, we present conclusions regarding the evidence-base for intermittent fasting as an intervention for improving human health and propose a research agenda. Table 1 Types of intermittent fasting regimens that are hypothesized to impact health outcomes This paper provides a uniquely broad synthesis of the scientific evidence linking intermittent fasting with human health and a framework for future research on this topic.

Prolonged Nightly Fasting and Breast Cancer Risk: Findings from NHANES (2009–2010)

Background: A novel line of research has emerged, suggesting that daily feeding–fasting schedules that are synchronized with sleep-wake cycles have metabolic implications that are highly relevant to breast cancer. We examined associations of nighttime fasting duration with biomarkers of breast cancer risk among women in the 2009–2010 U.S. National Health and Nutrition Examination Survey. Methods: Dietary, anthropometric, and HbA1c data were available for 2,212 women, and 2-hour postprandial glucose concentrations were available for 1,066 women. Nighttime fasting duration was calculated using 24-hour food records. Separate linear regression models examined associations of nighttime fasting with HbA1c and 2-hour glucose concentrations. Logistic regression modeled associations of nighttime fasting with elevated HbA1c (HbA1c ≥ 39 mmol/mol or 5.7%) and elevated 2-hour glucose (glucose ≥ 140 mg/dL). All models adjusted for age, education, race/ethnicity, body mass index, total kcal intake, evening kcal intake, and the number of eating episodes per day. Results: Each 3-hour increase in nighttime fasting (roughly 1 SD) was associated with a 4% lower 2-hour glucose measurement [β, 0.96; 95% confidence interval (CI), 0.93–1.00; P < 0.05], and a nonstatistically significant decrease in HbA1c. Logistic regression models indicate that each 3-hour increase in nighttime fasting duration was associated with roughly a 20% reduced odds of elevated HbA1c (OR, 0.81; 95% CI, 0.68–0.97; P < 0.05) and nonsignificantly reduced odds of elevated 2-hour glucose. Conclusions: A longer nighttime duration was significantly associated with improved glycemic regulation. Impact: Randomized trials are needed to confirm whether prolonged nighttime fasting could improve biomarkers of glucose control, thereby reducing breast cancer risk. Cancer Epidemiol Biomarkers Prev; 24(5); 783–9. ©2015 AACR.

Estudio Parto: Postpartum diabetes prevention program for hispanic women with abnormal glucose tolerance in pregnancy: A randomised controlled trial - study protocol

BackgroundDiabetes and obesity have reached epidemic proportions in the U.S. with rates consistently higher among Hispanics as compared to non-Hispanic whites. Among Hispanic women diagnosed with gestational diabetes mellitus (GDM), 50% will go on to develop type 2 diabetes within 5 years of the index pregnancy. Although randomised controlled trials among adults with impaired glucose tolerance have shown that diet and physical activity reduce the risk of type 2 diabetes, such programs have not been tested in high-risk postpartum women. The overall goal of this randomised controlled trial is to test the efficacy of a culturally and linguistically modified, individually-tailored lifestyle intervention to reduce risk factors for type 2 diabetes and cardiovascular disease among postpartum Hispanic women with a history of abnormal glucose tolerance during pregnancy.Methods/DesignHispanic pregnant women who screen positive for GDM will be recruited and randomly assigned to a Lifestyle Intervention (n = 150) or a Health & Wellness (control) Intervention (n = 150). Multimodal contacts (i.e., in-person, telephone, and mailed materials) will be used to deliver the intervention from late pregnancy (29 weeks gestation) to 12 months postpartum. Targets of the intervention are to achieve Institute of Medicine Guidelines for postpartum weight loss; American Congress of Obstetrician and Gynecologist guidelines for physical activity; and American Diabetes Association guidelines for diet. The intervention draws from Social Cognitive Theory and the Transtheoretical Model and addresses the specific cultural and environmental challenges faced by low-income Hispanic women. Assessments will be conducted at enrollment, and at 6-weeks, 6-months, and 12-months postpartum by trained bicultural and bilingual personnel blinded to the intervention arm. Efficacy will be assessed via postpartum weight loss and biomarkers of insulin resistance and cardiovascular risk. Changes in physical activity and diet will be measured via 7-day actigraph data and three unannounced 24-hour dietary recalls at each assessment time period.DiscussionHispanic women are the fastest growing minority group in the U.S. and have the highest rates of sedentary behavior and postpartum diabetes after a diagnosis of GDM. This randomised trial uses a high-reach, low-cost strategy that can readily be translated into clinical practice in underserved and minority populations.Trial registrationNCT01679210

Prolonged Nightly Fasting and Breast Cancer Prognosis

IMPORTANCE Rodent studies demonstrate that prolonged fasting during the sleep phase positively influences carcinogenesis and metabolic processes that are putatively associated with risk and prognosis of breast cancer. To our knowledge, no studies in humans have examined nightly fasting duration and cancer outcomes. OBJECTIVE To investigate whether duration of nightly fasting predicted recurrence and mortality among women with early-stage breast cancer and, if so, whether it was associated with risk factors for poor outcomes, including glucoregulation (hemoglobin A1c), chronic inflammation (C-reactive protein), obesity, and sleep. DESIGN, SETTING, AND PARTICIPANTS Data were collected from 2413 women with breast cancer but without diabetes mellitus who were aged 27 to 70 years at diagnosis and participated in the prospective Womens Healthy Eating and Living study between March 1, 1995, and May 3, 2007. Data analysis was conducted from May 18 to October 5, 2015. EXPOSURES Nightly fasting duration was estimated from 24-hour dietary recalls collected at baseline, year 1, and year 4. MAIN OUTCOMES AND MEASURES Clinical outcomes were invasive breast cancer recurrence and new primary breast tumors during a mean of 7.3 years of study follow-up as well as death from breast cancer or any cause during a mean of 11.4 years of surveillance. Baseline sleep duration was self-reported, and archived blood samples were used to assess concentrations of hemoglobin A1c and C-reactive protein. RESULTS The cohort of 2413 women (mean [SD] age, 52.4 [8.9] years) reported a mean (SD) fasting duration of 12.5 (1.7) hours per night. In repeated-measures Cox proportional hazards regression models, fasting less than 13 hours per night (lower 2 tertiles of nightly fasting distribution) was associated with an increase in the risk of breast cancer recurrence compared with fasting 13 or more hours per night (hazard ratio, 1.36; 95% CI, 1.05-1.76). Nightly fasting less than 13 hours was not associated with a statistically significant higher risk of breast cancer mortality (hazard ratio, 1.21; 95% CI, 0.91-1.60) or a statistically significant higher risk of all-cause mortality (hazard ratio, 1.22; 95% CI, 0.95-1.56). In multivariable linear regression models, each 2-hour increase in the nightly fasting duration was associated with significantly lower hemoglobin A1c levels (β = -0.37; 95% CI, -0.72 to -0.01) and a longer duration of nighttime sleep (β = 0.20; 95% CI, 0.14-0.26). CONCLUSIONS AND RELEVANCE Prolonging the length of the nightly fasting interval may be a simple, nonpharmacologic strategy for reducing the risk of breast cancer recurrence. Improvements in glucoregulation and sleep may be mechanisms linking nightly fasting with breast cancer prognosis.

Lifestyle Factors Associated with Cognitive Functioning in Breast Cancer Survivors

Weight, physical activity, and sleep are modifiable lifestyle factors that impact cognitive functioning in noncancer populations but have yet to be examined in cancer survivors. The aim of the study was to assess the relationship of obesity, physical activity, and sleep, with cognitive functioning among breast cancer survivors.

Impact of increasing physical activity on cognitive functioning in breast cancer survivors: Rationale and study design of Memory & Motion

INTRODUCTION Many breast cancer survivors experience problems with cognitive functioning that can persist years after treatment. Increasing physical activity has been shown to improve cognitive functioning in healthy and cognitively impaired adults, but has not yet been tested in cancer survivors. The primary aim of this randomized controlled trial is to examine the effects of a 3-month physical activity intervention compared to a waitlist Control arm on neuropsychological outcomes and subjective cognitive concerns in breast cancer survivors. METHODS Eighty sedentary breast cancer survivors, self-reporting difficulties with cognition, will be randomized into an Exercise arm or Control arm. The Exercise arm includes an activity tracker (i.e., a Fitbit), phone calls, plus tailored and non-tailored email content. The Control arm will receive emails on womens health topics on the same schedule as the Exercise arm. Assessments conducted at baseline and 3 months include: neuropsychological testing, cognitive concerns and other aspects of quality of life, and 7 days of a hip-worn accelerometer. Participants will also provide fasting blood draws to assess brain-derived neurotropic factor, Insulin-like growth factor 1, insulin resistance, and C-reactive protein. Primary and secondary outcomes are changes in neuropsychological testing and cognitive concerns. Biomarkers will be examined to further understand the underlying relationship between physical activity and cognition. CONCLUSION The Memory & Motion study is designed to test whether increasing physical activity can improve cognitive functioning in breast cancer survivors. Results from this study could be used to guide development of interventions to improve cognitive functioning in breast cancer survivors.

Clinical predictors of cognitive function in adults treated with hematopoietic cell transplantation

Studies suggest that patients with cancer who undergo hematopoietic cell transplantation (HCT) are at risk for cognitive deficits. To date, little research has investigated the cumulative effects of clinical risk factors on cognitive function in patients who undergo HCT.

Using interactive Internet technology to promote physical activity in Latinas: Rationale, design, and baseline findings of Pasos Hacia La Salud

Internet-based interventions show promise as an effective channel for promoting physical activity. However, a paucity of research has been conducted among underserved groups despite recent increases in Internet access and physical activity-related health disparities in these communities. Thus, the current randomized controlled trial will test the efficacy of an individually tailored, Internet-based physical activity intervention for Latinas. This program was culturally and linguistically adapted for the target population through extensive formative research. Two hundred eighteen sedentary Latinas were randomly assigned to the Tailored Physical Activity Internet Intervention or the Wellness Contact Control Internet Group. The Physical Activity Internet Intervention, based on Social Cognitive Theory and the Transtheoretical Model, utilizes a website with features including self-monitoring, goal setting, discussion forum, links to online resources, individually tailored and motivation-matched physical activity feedback reports, and exercise tip sheets. Participants receive regular emails over the first 6months with a tapered dose during the second 6months (maintenance phase) to alert them to new content on the website. The main outcome is differences in minutes/week of moderate to vigorous physical activity at six months as measured by the 7-Day Physical Activity Recall and accelerometer data. High reach, low cost, culturally relevant Internet-based interventions that encourage physical activity among Latinas could help reduce health disparities and thus have a substantial positive impact on public health.

Recruitment strategies, design, and participant characteristics in a trial of weight-loss and metformin in breast cancer survivors

Weight loss and metformin are hypothesized to improve breast cancer outcomes; however the joint impacts of these treatments have not been investigated. Reach for Health is a randomized trial using a 2 × 2 factorial design to investigate the effects of weight loss and metformin on biomarkers associated with breast cancer prognosis among overweight/obese postmenopausal breast cancer survivors. This paper describes the trial recruitment strategies, design, and baseline sample characteristics. Participants were randomized in equal numbers to (1) placebo, (2) metformin, (3) weight loss intervention and placebo, or (4) weight-loss intervention and metformin. The lifestyle intervention was a personalized, telephone-based program targeting a 7% weight-loss in the intervention arm. The metformin dose was 1500 mg/day. The duration of the intervention was 6 months. Main outcomes were biomarkers representing 3 metabolic systems putatively related to breast cancer mortality: glucoregulation, inflammation, and sex hormones. Between August 2011 and May 2015, we randomized 333 breast cancer survivors. Mass mailings from the California Cancer Registry were the most successful recruitment strategy with over 25,000 letters sent at a cost of