Human biology and the study of precarity: How the intersection of uncertainty and inequality is taking us to new extremes.

Inequality represents an extreme environment to which humans must respond. One phenomenon that contributes to this growing extreme is precarity or the intersection of uncertainty and some form of inequality. While precarity has an important intellectual history in the fields of sociology and sociocultural anthropology, it has not been well studied in the field of human biology. Rather human biologists have engaged with the study of closely related concepts such as uncertainty and resource insecurity. In this article, we propose that human biology take on the study of precarity as a novel way of investigating inequality. We first provide a brief intellectual history of precarity which is followed by a review of research on uncertainty and resource security in human biology which, while not exhaustive, illustrates some key gaps that precarity may aid us in addressing. We then review some of the pathways through which precarity comes to affect human biology and health and some of the evidence for why the unpredictable nature of precarity may make it a unique physiological stress. A case study based on research in Nuñoa, Peru provides an important example of how precarity can elucidate the influences of health in an extreme setting, albeit with insights that apply more broadly. We conclude that precarity holds important potential for the study of human biology, including helping us more effectively operationalize and study uncertainty, encouraging us to explore the predictability of resources and stressors, and reminding us to think about the intersectional nature of stressors.

Systemic inflammation and menstrual cycle length in a prospective cohort study.

BACKGROUND: Local inflammation plays an important role in normal folliculogenesis and ovulation, and conditions of chronic systemic inflammation, such as obesity and polycystic ovarian syndrome, can disrupt normal follicular dynamics. OBJECTIVE: This study aimed to determine the association between systemic inflammation, as measured by C-reactive protein levels, and menstrual cycle length. STUDY DESIGN: This study was a secondary analysis using data from Time to Conceive, a prospective time-to-pregnancy cohort study. The association between cycle length and C-reactive protein was analyzed using multivariable linear mixed and marginal models adjusted for age, race, education, body mass index, time since oral contraceptive use, alcohol, smoking, caffeine consumption, and exercise. Time to Conceive enrolled women aged 30 to 44 years with no history of infertility who were attempting to conceive for <3 months. Serum C-reactive protein levels were measured on cycle day 2, 3, or 4. Participants recorded daily menstrual cycle data for ≤4 months. RESULTS: Main outcome measures included menstrual cycle length and follicular and luteal phase lengths. Multivariable analysis included 1409 cycles from 414 women. There was no linear association between C-reactive protein levels and menstrual cycle length. However, compared with <1 mg/L, a C-reactive protein level >10 mg/L was associated with >3 times the odds (adjusted odds ratio, 3.7; 95% confidence interval, 1.67-8.11) of long cycles (defined as ≥35 days). When evaluating follicular phase length, a C-reactive protein level of >10 mg/L was associated both with follicular phases that were 1.7 (95% confidence interval, 0.23-3.09) days longer and with >2 times the odds of a long follicular phase (adjusted odds ratio, 2.2; 95% confidence interval, 1.05-4.74). CONCLUSION: There is a potential pathophysiological association between systemic inflammation and menstrual cycle changes. Further studies are needed to determine if systemic inflammation alters the menstrual cycle or if long menstrual cycles are a marker for elevated systemic inflammation.