Brown Adipose Tissue, Biological Variation and Senescence in Humans

University Of Massachusetts Amherst, Amherst MA

Investigators

Abstract

Fundamental research in human biology includes efforts to understand the nature and tempo of human life history, including the timing and characteristics of aging in various physiological systems. This project focuses on hot flashes as an aspect of human variation during reproductive aging, and tests the hypothesis that brown adipose tissue - a type of fat that generates heat - may be a factor associated with hot flash experience. The study will extend our knowledge about human variation in both brown adipose tissue and hot flash experience, with particular attention to the relation between hot flashes (subjectively reported and biometrically measured), brown adipose tissue, body composition, and climate. The study will address human variation in the ability to generate and dissipate heat, and findings will contribute to knowledge about modern human biological adaptations. The outcomes of this research may also inform clinical understanding and treatments of conditions that affect many women in the U.S., including hot flashes and obesity. Results from this study will be shared with participants and communities through public talks, brochures and a project website. Undergraduate women will assist with the research, thereby gaining valuable experience in STEM fields. When brown adipose tissue is activated by cool or cold conditions, it creates heat in an effort to keep the body warm. The central hypothesis of this study is that brown adipose tissue activation may produce enough heat to cause hot flashes. The aim is to explore the role of brown adipose tissue activation in the experience of hot flashes among peri-menopausal and early postmenopausal women, aged 45-55, during the cold months -- from late October to early April -- in western Massachusetts. The investigators hypothesize that (1) women with more brown adipose tissue activity will be more likely to objectively demonstrate and subjectively report hot flashes, (2) brown adipose tissue activity is more likely to be associated with hot flashes in heavier women, and (3) acclimatization to heat and (4) exposure to lower ambient temperatures amplify the association between brown adipose tissue activity and hot flashes. The study involves face-to-face interviews about hot flashes and factors associated with hot flashes, physical activity, and stress; body measurements (height, weight, skinfolds, waist and hip circumferences); body composition by bioelectrical impedance; an estimation of brown adipose tissue activity with an infrared camera before and after dipping a hand into cool (64oF) water for five minutes; an ambulatory hot flash monitor worn for 24 hours to record both objective and subjective hot flashes; and an Actigraph GT9X watch to measure activity and sleep patterns for the same 24 hours. On the hot flash monitor pouch, there will also be a small ambulatory gauge to measure air temperature and humidity. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.