Habitual caffeinated beverage consumption and headaches among adults with episodic migraine: A prospective cohort study.

OBJECTIVE: To examine the relationship between habitual caffeinated beverage consumption and headache frequency, duration, and intensity in a prospective cohort of adults with episodic migraine. BACKGROUND: Caffeine is a commonly ascribed headache trigger in adults with migraine and clinicians may counsel patients to avoid caffeinated beverages; however, few studies have examined this association. METHODS: From March 2016 to August 2017, 101 adults with physician-confirmed episodic migraine completed baseline questionnaires, including information about caffeinated beverage consumption. For 6 weeks, they reported headache onset, duration, and pain intensity (scale 0-100) on twice-daily electronic diaries. Ninety-seven participants completed data collection. We examined associations between self-reported habitual caffeinated beverage consumption at baseline and headache outcomes prospectively captured over the following 6 weeks, adjusting for age, sex, and oral contraceptive use. RESULTS: The adjusted mean headache days per month was similar among the 20 participants reporting no habitual intake (7.1 days, 95% confidence interval [CI] 5.1-9.2), the 65 participants reporting 1-2 servings/day (7.4 days, 95% CI 6.1-8.7), and the 12 participants reporting 3-4 servings/day (5.9 days, 95% CI 3.3-8.4). Similarly, mean headache duration (no servings/day: 8.6 h, 95% CI 3.8-13.3; 1-2 servings/day: 8.5 h, 95% CI 5.5-11.5; 3-4 servings/day: 8.8 h, 95% CI 2.3-14.9) and intensity (no servings/day: 43.8, 95% CI 37.0-50.5; 1-2 servings/day: 43.1, 95% CI 38.9-47.4; 3-4 servings/day: 46.5, 95% CI 37.8-55.3) did not differ across levels of caffeinated beverage intake, though estimates were imprecise. CONCLUSIONS: We found no association between habitual caffeinated beverage intake and headache frequency, duration, or intensity. These data do not support a recommendation that patients with episodic migraine should avoid consuming caffeine. Further research is needed to understand whether deviating from usual caffeine intake may trigger migraine attacks.

Exposure to hazardous air pollutants and risk of incident breast cancer in the nurses' health study II.

BACKGROUND: Findings from a recent prospective cohort study in California suggested increased risk of breast cancer associated with higher exposure to certain carcinogenic and estrogen-disrupting hazardous air pollutants (HAPs). However, to date, no nationwide studies have evaluated these possible associations. Our objective was to examine the impacts of mammary carcinogen and estrogen disrupting HAPs on risk of invasive breast cancer in a nationwide cohort. METHODS: We assigned HAPs from the US Environmental Protection Agency's 2002 National Air Toxics Assessment to 109,239 members of the nationwide, prospective Nurses' Health Study II (NHSII). Risk of overall invasive, estrogen receptor (ER)-positive (ER+), and ER-negative (ER-) breast cancer with increasing quartiles of exposure were assessed in time-varying multivariable proportional hazards models, adjusted for traditional breast cancer risk factors. RESULTS: A total of 3321 invasive cases occurred (2160 ER+, 558 ER-) during follow-up 1989-2011. Overall, there was no consistent pattern of elevated risk of the HAPs with risk of breast cancer. Suggestive elevations were only seen with increasing 1,2-dibromo-3-chloropropane exposures (multivariable adjusted HR of overall breast cancer = 1.12, 95% CI: 0.98-1.29; ER+ breast cancer HR = 1.09; 95% CI: 0.92, 1.30; ER- breast cancer HR = 1.14; 95% CI: 0.81, 1.61; each in the top exposure quartile compared to the lowest). CONCLUSIONS: Exposures to HAPs during adulthood were not consistently associated with an increased risk of overall or estrogen-receptor subtypes of invasive breast cancer in this nationwide cohort of women.