. 2018 Jul 27;8:11375. doi: 10.1038/s41598-018-29747-2

Table 3.

Association of UNGD and depression symptoms identified via the eight-item Patient Health Questionnaire-8 (PHQ-8) depression scale in weighted survey negative binomial models (n = 4,762^a).

UNGD group^b	Depression symptoms^c
UNGD group^b	Exponentiated coefficient^d (95% CI)
Very low	1.00
Low	1.14 (1.01–1.29)
Medium	1.03 (0.91–1.17)
High	1.18 (1.04–1.34)

Abbreviations: CI = confidence interval; UNGD = unconventional natural gas development.

^aExcludes follow-up responders outside of Pennsylvania (n = 34) and those that answered no depression symptom questions (n = 170).

^bThe UNGD metric was a composite for four phases of well development (pad preparation, drilling, stimulation, and production) and was assigned for the two weeks prior to follow-up survey return.

^cModels included truncated survey weights and adjusted for race/ethnicity (White non-Hispanic, Black non-Hispanic, Hispanic), sex (male, female), Medical Assistance (no, yes), age (years, linear and quadratic terms), smoking status (never, former, current), alcohol status (no; yes, not heavy; yes, heavy), body mass index (BMI, kg/m², linear and quadratic terms), community socioeconomic deprivation (linear and quadratic terms), and water source (municipal water, well water).

^dRatio of mean symptom counts.