Depressed mood and cause-specific mortality: a 40-year general community assessment 박세진

Introduction Depression is considered to be the leading cause of disability in the world But, how depression contributes to mortality is unknown Association between depression and elevated total mortality risk in the general community - Meta-analysis (25 studies) : overall RR is 1.81 ( ) - Elderly in Japan (15-year follow-up study) : cerebrovascular diseas, cancer, respiratory disorder, and suicide - Middle-aged adults in the Netherlands(5-year follow-up study) : cardiovascular disease, cancer, and accidents

Purpose : - Examined the causes of death associated with depressed mood in a general community study during a 40-year follow-up period - By specific causes of death : focus on deaths related to injuries, cardiovascular diseases (CVD), and cancer - Describes how the excess mortality risk associated with depression

Methods Study population - Data source : cross-sectional survey (Community Mental Health Epidemiology Study, CMHE) - Conducted in the early 1970s in Washington County, Maryland - Interviewing during ~ Sampling for CMHE : 1963 년에 수행된 자치주 센서스 자료의 가구명단을 이용, 지역 및 사회경제학적 특성별 층화 랜덤 가구 추출, 18 세 이상 가구원 2,762 명 조사대상 ( 응답률 78%)

Exposure measurement : depressed mood - measured at the Baseline (CMHE survey) - CES-D scale (Center for Epidemiologic Studies Depression scale) 사용 - Depressed mood : CES-D ≥ 16 Outcome measurement : mortality linkage - linked to mortality status over 40 years through the use of three main mortality sources

Three main mortality sources 1. Washington County death certificates : 1972~2011 에 발생한 사망자와 매칭 2. NDI (National Death Index): 1 번의 자료에서 확인되지 않은 대상자는 NDI 에서 사망확인 (1979~2008) 3. SSDI (Social Security Death Index) : 2 번째 까지 확인되지 않은 대상자는 마지막으로 최근 사망자 자료에서 확인 ( ~2011.8) * 위의 세자료에서 사망이 확인되지 않은 대상자는 월 기준 생존한것으로 가정

Outcome measurement : cause of death determination - 모든 대상자 중 1477(95.5%) 명 사망원인 확인 가능 - 사망원인 코드는 ICD (International Classification of Diseases) 로 분류 - three disease categories 1) Cardiovascular disease : diseases of the heart, cerebrovascular diseases, essential hypertension and hypertensive renal diseases 2) Cancer : any malignant neoplasm 3) Fatal injuries : accidents(unintentional injuries), intentional self-harm (suicide), and assault(homicide) 4) Other cause of death : 이 외 사망원인

Covariates ( 조사 당시 특성 ) - 연령, 성별, 흡연상태 (ever vs never), 교육정도 ( 고등학교 이상 vs 미만 ), BMI (healthy : ) - adjustment by regression models

Analysis - Cause-specific Cox proportional Hazards model 적용 * outcomes : each major cause of death - Subdistribution cumulative incidence function 사용 : due to presence of competing risks (other cause of death) in this analysis, alternative measure of risk used * competing risks : “ 목적하는 event” 발생이 예상치 못한 “ 다른 event” 발생으로 인해 목적하는 event 가 발생하지 못할 경우 다른 event 가 competing risk 가 됨 ex> stroke 환자 : event (vascular death), competing risk (cancer death)

-Stacked cumulative incidence plots -Sensitive analyses: baseline 에서 이미 신체질환에 이환된 대상자를 제외시키기 위해, follow up 5 년 이내 사망자 제외 - Stratafied : 1) follow-up time (0 to <15 y, 15 to <30y, 30 to 40y) 2) age group (18-39, 40-64, 65~) - Stata v.11

Result

Mortality (36.2% vs 18.8%, p<.001)

Mortality (16.8% vs 11.9%, p=.12)

Discussion Association between depressed mood and cause- specific mortality differ by sex, age group, proximity to baseline Young adult females with depressed mood and CVD death risk (4 of 8 all death, 0 death in no depressed) * emergency of depression in young adult have strong genetic basis * the genetic link to depression is associated with future development of CVD Young adult males with depressed mood and fatal injury in time periods closer to baseline * excess mortality risk associated with depression is not explained by excess suicide deaths * fatal injuries were important cause of death among middle-aged males without depressed in this study

Limitation - 사망진단서의 정확성 * circulatory disorders 의 과대기술, 의도 / 비의도적 손상 구분의 모호함 및 잘못 분류 - CVD 와 같은 질환을 세부적으로 분류하는 것보다 하나로 묶을 때의 misclassification 이 더 흔함