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Table 1 Patient demographics, healthcare utilization, and environmental exposures for migraine cases and controls from Sutter Health in Northern California, 2014–2018

From: Air pollution, methane super-emitters, and oil and gas wells in Northern California: the relationship with migraine headache prevalence and exacerbation

  Migraine cases
N = 89,575
Controlsa
N = 270,564
Patient Demographics
Age Category, N (%)
  18–29 years 16,952 (18.9) 51,112 (18.9)
  30–44 years 33,036 (36.9) 99,792 (36.9)
  45–54 years 19,226 (21.5) 58,169 (21.5)
  55–64 years 12,578 (14.0) 38,093 (14.1)
   ≥ 65 years 7783 (8.7) 23,399 (8.7)
Sex, N (%)
  Female 73,908 (82.5) 223,230 (82.5)
  Male 15,667 (17.5) 47,334 (17.5)
Race/Ethnicity, N (%)
  Non-Hispanic
   Asian 9278 (10.4) 52,794 (19.9)
   Black 3685 (4.1) 10,253 (3.8)
   White 52,579 (58.7) 130,418 (48.2)
   Other 11,351 (12.7) 41,907 (15.5)
  Hispanic 12,682 (14.2) 34,192 (12.6)
Marital Status, N (%)
  Divorced/Separated/Widowed 7444 (8.3) 18,881 (7.0)
  Married/Significant Other 51,390 (57.4) 155,644 (57.5)
  Single 22,659 (25.3) 63,801 (23.6)
  Other/Unknown 8082 (9.0) 32,238 (11.9)
Body Mass Index Category (kg/m3), N (%)
  Underweight (< 18.5) 1672 (1.9) 5636 (2.0)
  Normal (18.5–24.9) 33,801 (37.7) 112,014 (41.4)
  Overweight (25–29.9) 26,969 (30.1) 79,209 (29.3)
  Obese Class 1 (30–34.9) 14,595 (16.3) 39,405 (14.6)
  Obese Class 2 (35–39.9) 6835 (7.6) 17,388 (6.4)
  Obese Class 3 (40+) 4614 (5.2) 11,658 (4.3)
  Missing 1089 (1.2) 5254 (1.9)
Block Group-Level Variables, Median (IQR)
  Percent Poverty 7.2 (3.5, 14.3) 6.6 (3.2, 13.1)
  Population Density (individuals per km2) 2211 (901, 3593) 2292 (954, 3592)
Medicaid Beneficiary, N (%)
  Yes 6929 (7.7) 15,105 (5.6)
  No 82,646 (92.3) 255,459 (94.4)
Healthcare Utilization
Encounters per person-year
  Primary care, Median (IQR) 2.4 (1.4, 4.0) 1.9 (1.2, 3.1)
  Neurology, Mean (SD) 1.2 (3.4) 0.2 (1.0)
  Urgent Care (Migraine-Specific), Mean (SD) 0.2 (2.7)
  Emergency (Migraine-Specific), N (%) 0.1 (0.7)
    ≥ 1 visit during the study period 3987 (4.5)
    < 1 visit during the study period 85,588 (95.5)
Triptan prescriptions per person-year, mean (SD) 0.6 (2.6)  
MPA Score – N (%) 66.6 (31.5)
   11 - 100 59,599 (66.5)
   > 100 29,976 (33.5)
Environmental Exposures
Air Pollutants, Median (IQR)
  NO2, ppb 7.7 (5.7, 10.2) 8.1 (5.9, 10.4)
  PM2.5, μg/m3 8.7 (7.8, 9.6) 8.9 (7.8, 9.7)
CH4 Emissions
  Any super-emitter within 10 km, N (%) 18,457 (20.6) 57,224 (21.1)
  Total IDW emissions in kg/hour, Mean (SD) 21,461 (192,973) 26,070 (180,548)
Active Oil and Gas wells
  Any oil or gas well within 10 km, N (%) 13,179 (14.7) 37,010 (13.7)
  Total IDW wells, Mean (SD) 604 (6468) 603 (6459)
  1. IDW Inverse-distance weighted; IQR Interquartile range; MPA Migraine probability algorithma Frequency-matched on age category, sex, year of entry into Sutter primary care, and primary-care follow-up time (0–6 months, 7–24 months, ≥ 24 months)