Perspectives on the Future of Epidemiology: A Framework for Training

Over the past century, the field of epidemiology has evolved and adapted to changing public health needs. Challenges include newly emerging public health concerns across broad and diverse content areas, new methods, and vast data sources. We recognize the need to engage and educate the next generation of epidemiologists and prepare them to tackle these issues of the 21st century. In this commentary, we suggest a skeleton framework upon which departments of epidemiology should build their curriculum. We propose domains that include applied epidemiology, biological and social determinants of health, communication, creativity and ability to collaborate and lead, statistical methods, and study design. We believe all students should gain skills across these domains to tackle the challenges posed to us. The aim is to train smart thinkers, not technicians, to embrace challenges and move the expanding field of epidemiology forward.

Posttraumatic Stress Disorder 23 Years After the 1988 Spitak Earthquake in Armenia

This population-based longitudinal study examined the rates and predictors of posttraumatic stress disorder (PTSD) among 725 differentially exposed survivors of the 1988 Spitak earthquake in Armenia, 23 years after the event. Participants had been previously evaluated in 1991. Evaluations included assessment of current PTSD (based on DSM-5 criteria), and a variety of potential risk and protective factors. For the whole sample, the rate of PTSD attributed to the earthquake decreased from 48.7% in 1991 to 11.6% in 2012 (p < .001). A "dose of exposure" pattern persisted, and 15.7% of participants who were in Spitak (high exposure) and 6.6% of participants who were in Kirovagan (low exposure) during the earthquake met the criteria for PTSD (p = .003). Additionally, in 2012, another 9.9% of participants met PTSD criteria due to post-earthquake traumas, which is a 5-fold increase from pre- to postearthquake (p < . 001). Factors positively associated with PTSD included earthquake-related job loss, exposure to post-earthquake traumas, depression at baseline, and chronic illness since the earthquake. Factors inversely associated with PTSD included housing assistance within two years after the earthquake, support of family and/or friends, and to a lesser degree, higher education and high living standard. These variables accounted for 23.1% of the variance in current PTSD severity scores. These findings indicate that PTSD rates subside significantly after a catastrophic disaster, although earthquake-related PTSD persists among a subgroup of exposed individuals. Predictors of PTSD identified in this study provide guidance for planning acute and longer-term postdisaster public mental health recovery programs.

A post-earthquake psychopathological investigation in Armenia: methodology, summary of findings, and follow-up

The post-earthquake psychopathological investigation (PEPSI) was designed to probe the short-and long-term effects of the earthquake in northern Armenia on 7 December 1988 on survivors' mental and physical health. Four phases of this study have been conducted to date, and, overall, more than 80 per cent of a sub-sample of 1,773 drawn from an initial cohort of 32,743 was successfully followed during 2012. This paper describes the methodology employed in the evaluation, summarises previous findings, details the current objectives, and examines the general characteristics of the sample based on the most recent follow-up phase outcomes. Despite a significant decrease in psychopathology rates between 1990 and 2012, prevalence rates of post-traumatic stress disorder and depression among study participants in 2012 were greater than 15 and 26 per cent, respectively. The paper also notes the strengths and limitations of the study vis-à-vis future research and highlights the importance and potential practical implications of similar assessments and their outcomes.

Interbirth interval and history of previous preeclampsia: a case-control study among multiparous women

Background

Preeclampsia is a disorder with a reported incidence of 2%-8% among all pregnancies, accounting for more than 50,000 deaths worldwide each year. In low- and middle- income countries maternal/perinatal morbidity and mortality associated with preeclampsia are high due to the lack of proper prenatal and hospital care and limited access to neonatal intensive care. The objectives of our study were to determine the association of long interbirth interval (IBI) and preeclampsia and to investigate the interactions between long IBI and other risk factors among multiparous women in Yerevan, Armenia.

Methods

We conducted a hospital-based case–control study among 36 multiparous women with preeclampsia (cases) and 148 without preeclampsia (controls) during their last pregnancy, selected from the two largest maternity hospitals in Armenia. The data were collected through telephone-based structured interviews and analyzed using STATA software. The study applied univariate and multivariate logistic regression analyses.

Results

The study found a significant interaction between IBI and previous history of preeclampsia. Among women without a history of previous preeclampsia, the odds of having preeclampsia among women with long IBI (greater than or equal to five years) was 6.88 time higher compared to those with short IBI (CI: 1.75-27.05; p = 0.006) after adjusting for confounders; among women with a history of previous preeclampsia the odds ratio was 0.60 (CI: 0.07-4.99; p = 0.638). The final fitted model for preeclampsia among multiparous women who had planned their pregnancies included IBI, time to pregnancy, Body Mass Index, method of contraception and household monthly income.

Conclusions

Long IBI appeared to be a strong risk factor for preeclampsia development only among women without a history of previous preeclampsia. This finding may contribute to a new approach in understanding the etiology of preeclampsia and may be useful for developing further recommendations for this particular subgroup of women that are at higher risk for preeclampsia development in subsequent pregnancies.

occupational physical activity and the development of impaired mobility: the 12-year follow-up of the Baltimore Epidemiologic Catchment Area sample

OBJECTIVE

To examine the association between occupational physical activity and self-reported disability.

DESIGN

Population-based case control analysis of a longitudinal population-based study in east Baltimore. Eligible participants were aged 18 to 29 yr in 1981, had complete information on occupation in 1981, no disability with tasks related to the domain of mobility in 1981, and complete information on mobility function in 1993 (n = 174). Occupations were divided into low, moderate, and high metabolic equivalents based on job category in 1981. The main outcome measure was disability defined by self-report of difficulty in one or more of five exercise mobility tasks in 1993.

RESULTS

Of 174 eligible participants, 45 (26%) reported the onset of disability at follow-up in 1993. A crude odds ratio of 0.25 (95% confidence interval, 0.06, 0.82) was found for the association of moderate compared with low occupational physical activity and the risk of incident disability in mobility tasks. After adjustments to control for possible confounders, moderate job metabolic activity (1.8-2.9 Mets) was independently protective against disability in this cohort (odds ratio = 0.25; 95% confidence interval = 0.083, 0.783).

CONCLUSION

In this cohort of people aged 18 to 29 yr, a moderate amount of occupational physical activity was protective against disability in mobility tasks.

Interaction of human immunodeficiency virus type 1 and human herpesvirus type 8 infections on the incidence of Kaposi's sarcoma

To determine Kaposi's sarcoma (KS) risk related to timing of human immunodeficiency virus type 1 (HIV-1) and human herpesvirus type 8 (HHV-8) infections, stored longitudinal sera from 400 homosexual men with known dates of HIV-1 seroconversion (+/-4.5 months) were tested for HHV-8 antibody. Times from HHV-8 seroconversion to KS were compared for the 69 men who became infected with HHV-8 after acquiring HIV-1 to the 182 men who were HHV-8 seropositive before their HIV-1 infection. None developed KS before coinfection. HHV-8 seroconversion after HIV-1 infection increased the risk of KS (risk ratio, 2.55; 95% confidence interval, 1.06-6.10) compared with those infected with HHV-8 before HIV-1. The KS hazards in HHV-8-infected men increased by 60% (P<.001) for each year of HIV-1 infection. Faster CD4 cell loss and higher HIV-1 RNA levels significantly predicted KS. The quicker development of KS in men acquiring HHV-8 after HIV-1 and its association with CD4 slope argues that KS is more likely if HHV-8 infection occurs in an immunocompromised person.

Elevated HPRT mutation frequencies in aflatoxin-exposed residents of daxin, Qidong county, People's Republic of China

Molecular biomarkers are becoming increasingly important tools to identify people who are at highest risk of developing cancer. For many years we have been studying residents of Qidong County, People's Republic of China, to examine the combined impact of aflatoxin exposure with other risk factors as contributors to the high liver cancer incidence rates in this region. This study was conducted to determine the effects of aflatoxin exposure, as measured by serum aflatoxin-albumin adduct levels, on somatic mutation frequency in the human hypoxanthine guanine phosphoribosyl transferase gene (HPRT). Subjects were assigned as low or high according to a dichotomization around the population mean of aflatoxin-albumin adducts. HPRT mutant frequency was determined in individuals by a T cell clonal assay and the samples were categorized as low or high according to mean values. Separate analyses were also conducted for the small set of hepatitis B virus surface antigen (HBsAg)-positive and the larger set of HBsAg-negative individuals, known risk factors for liver cancer. An odds ratio of 19.3 (95% confidence interval 2.0, 183) was demonstrated for a high HPRT mutation frequency in individuals with high aflatoxin exposure compared with those with low aflatoxin exposure. This association indicates that aflatoxin-induced DNA damage in T lymphocytes, assessed using the validated surrogate albumin adduct markers, leads to increased mutations reflected as elevated HPRT gene mutations. This cross-sectional study suggests the potential use of mutation frequency of the HPRT gene as a long-term biomarker of aflatoxin exposure in high risk populations.

Reductions in high-risk drug use behaviors among participants in the Baltimore needle exchange program

OBJECTIVE

To determine whether enrollment in the Baltimore Needle Exchange Program (NEP) was associated with short-term reduction in risky injection practices.

METHODS

Demographic information was collected on NEP participants upon enrollment. A systematic sample of enrollees was interviewed at program entry, 2 weeks, and 6 months later on recent drug-related behaviors. Comparisons were performed using paired t-tests.

RESULTS

Among 221 NEP participants who completed baseline, 2-week and 6-month follow-up visits, significant reductions (p < .01) were reported in using a previously used syringe (21.6%, 11.0%, 7.8%, respectively), lending one's used syringe to a friend (26.7%, 18.4%, 12%, respectively), and several indirect sharing activities. Reductions were reported in the mean number of injections per syringe and the mean number of injections per day (p < .001).

CONCLUSIONS

These results show rapid and mostly large reductions in a variety of risky injection drug use behaviors. Study findings are consistent with earlier reports showing an association between behavioral risk reduction and participation in a needle exchange program.

Depression and risk for onset of type II diabetes. A prospective population-based study

OBJECTIVE

To determine whether depression is associated with an increased risk for onset of diabetes.

RESEARCH DESIGN AND METHODS

In 1981, a total of 3,481 household-residing adults participated in the Epidemiologic Catchment Area (ECA) Program survey at the East Baltimore site. A follow-up of that cohort after 13 years completed 1,897 interviews, amounting to > 72% of survivors. In 1981, depression was assessed with the National Institutes of Mental Health (NIMH) Diagnostic Interview Schedule and diabetes, by self-report. This prospective analysis focused on subjects at risk for onset of diabetes by removing from the analysis individuals with diabetes in 1981.

RESULTS

There were 89 new cases of diabetes among 1,715 individuals at risk, yielding a 13-year cumulative incidence of diabetes of 5.2%. In logistic models, major depressive disorder, but not milder forms of depression or other forms of psychiatric disorder, predicted the onset of diabetes (estimated relative risk, 2.23; 95% CI 0.90-5.55). Controlling for age, race, sex, socioeconomic status, education, use of health services, other psychiatric disorders, and body weight did not weaken the relationship.

CONCLUSIONS

Major depressive disorder signals increased risk for onset of type II diabetes. Limitations of the findings arise from the difficulty in determining temporal order with two chronic conditions, even when the temporal order of measurement is clear. In addition, even though control variables were introduced for the use of health services, it is possible that the treatment for depression led to an earlier diagnosis of diabetes in this sample.

Longitudinal study of homosexual couples discordant for HIV-1 antibodies in the Baltimore MACS Study

Thirty-six sexually active couples serologically discordant for human immunodeficiency virus, type 1 (HIV-1), within the Baltimore Multicenter AIDS Cohort Study (MACS) were assessed to determine whether evidence of HIV-1 infection could be detected in the HIV-1-antibody-negative partners and whether factors associated with lack of transmission of HIV from the seropositive to the seronegative partner could be ascertained. Six HIV-1 seropositive couples and 18 seronegative couples were followed concurrently for comparison. None of the seropositive subjects had an AIDS-defining illness at entry into the study, and all subjects were followed for 1 year. A separate evaluation of unprotected anal receptive and insertive intercourse between discordant couples indicated high-risk activities for a median of 40 months, as reported by the HIV seropositive partner. Despite this finding, none of the HIV-1 seronegative men in discordant couples had evidence of HIV-1 infection by viral culture, p24 antigen testing, or polymerase chain reaction for HIV-1 DNA. Discordant seronegatives and seropositives did not differ from concordant seronegatives and seropositives in numbers of circulating CD4, CD8, and natural killer lymphocytes or in prevalence of antibodies to herpes simplex virus, type 1, Epstein-Barr virus, or cytomegalovirus, except that discordant seronegative men were less likely than their seropositive partners to have antibodies to herpes simplex virus, type 2. The reason for the apparent lack of HIV-1 infection in seronegative discordant individuals remains unexplained and did not appear to be associated with type of sexual activity, T-lymphocyte subsets or natural killer cells, or early stage of HIV-1 disease.

The effect of education and written material on compliance of pediatric clients

One hundred and fifty babies and their mothers, presenting to the Well Baby Clinic of the Pediatric Outpatient Department were studied for compliance. They were divided randomly into three groups, one serving as a control (n = 55) and two as experimental groups (n = 48 and 47). The latter were exposed to two different intervention methods; teaching and written material respectively, in addition to the routine care given to the control group. The three groups were compared in terms of compliance and improvement in knowledge. The results showed that reinforcement of the doctor's advice by a nurse, or written instructions to the patients, did not improve knowledge or compliance. Possible explanations for such results are given and suggestions for other modes of intervention are made.

Patient compliance in a well baby clinic. Effect of two modes of intervention

One hundred and fifty babies and their mothers, presenting to the Well Baby Clinic of the Pediatric Outpatient Department were studied for compliance. They were divided randomly into three groups, one serving as a control [n = 55] and two as experimental groups [n = 48 and n = 47 respectively]. The latter were exposed to two different intervention methods respectively, in addition to the routine care given to the control group. The three groups were compared in terms of compliance and improvement in knowledge. The results showed that reinforcement of the doctor's advice by a nurse, or written instructions to the patients, did not improve knowledge nor compliance. Possible explanations for such results are given and suggestions for other modes of intervention are made.

A population-based survey of loss and psychological distress during war

Research on the psychological effects of war has been conducted on a limited number of population groups and has generally failed to study the experience of particular losses while warfare was still in progress. This paper presents the results of a household surveillance study of 5788 displaced and non-displaced civilians conducted during the summer 1982 war in Lebanon. In order to determine demographic differences in the psychological response to war and help identify population groups possibly at-risk for mental disorder, an interview checklist of symptoms of psychological distress was developed and administered to a key informant in each household. The occurrence of psychological distress symptoms varied significantly by age, sex, nationality, socio-economic status, loss of physical health and economic loss. A more detailed analysis of the psychological effect of displacement or loss of one's home during war is presented. Displacement group differentials suggest that psychological distress may be more frequently perceived post-war and that both social integration and social isolation may play important roles in mediating the perception of psychological distress during war.