Cover Letter 7

Tesfa Dejenie Habtewold
Department of Psychiatry and Epidemiology
University of Groningen
Hanzeplein 1
Groningen, 9713 GZ
[email protected]
+316 3015 6447

24 October 2019

Dr. Kristine Yaffe
Principal Investigator, University of California at San Francisco and San Francisco Veterans Affairs Medical Center
4150 Clement Street (116H), San Francisco, CA 94121
Tel: 415-221-4810 x23792
Fax: 415-379-5624

Dear Dr. Kristine Yaffe,

I am writing to apply for the postdoctoral research fellow position in the epidemiology of brain health with a primary focus on cognitive disorders and dementia in the Center for Population Brain Health, Departments of Psychiatry, Neurology, and Epidemiology & Biostatistics at the University of California at San Francisco and San Francisco Veterans Affairs Medical Center as advertised on the Epidemiology Monitor (www.epiMonitor.net). I am a Ph.D. student at University of Groningen in University Center for Psychiatry and department of life course Epidemiology, where healthy aging is the main research focus, working under the supervision of professor Richard Bruggeman (Neuropsychiatrist), professor Marike Boezen (Epidemiologist) and Dr. Behrooz Z. Alizadeh (expert Epidemiologist). I expect to submit my thesis in the coming three to six months and receive my Ph.D. degree in September 2020. My experiences on longitudinal big data analysis, trajectory analysis of diseases symptoms and machine learning at the University of Groningen along with my life course epidemiology training background, make me a strong candidate to the research fellowship.

The aim of my Ph.D. project is to unravel the cardiometabolic and neuropsychiatric risk factors and outcomes in patients with a schizophrenia spectrum disorders, their unaffected siblings and healthy controls using family-based cohort data in Dutch population. In a cross-sectional study (Study I) involving 1,129 patients with schizophrenia spectrum disorder, I found a significant association between glycated hemoglobin level and high body mass index, blood pressure and cholesterol, age of diseases onset, use of antipsychotic drugs, and polygenic risk score of schizophrenia (PRS_SCZ) and type 2 diabetes (PRS_T2D). In a systematic review (Study II) of 49 cluster- and trajectory-based studies conducted in 30 countries,  I found two to five subtypes of neurocognitive deficits, and positive and negative symptoms/schizotypy with variable long-term trajectories in patients with schizophrenia spectrum disorders, their siblings and healthy people. Numerous environmental factors, including cognitive activity, depressive and somatic symptoms, lifestyle activity, general psychopathology and severity of diseases symptoms  predicted subtypes and longitudinal trajectories. In the 10 years longitudinal cohort study (Study III to V) involving 1,136 patients with schizophrenia spectrum disorders, 1,045 unaffected siblings and 583 healthy controls, I applied a combination of group-based trajectory modelling and multilevel analysis to examine heterogeneity and predictors. I discovered cognitive impairment, and positive and negative symptoms are more heterogeneous than currently recognized and associated with poor cardiometabolic health, severity of symptoms, cognitive activity, and genetic susceptibility (i.e. PRS_SCZ).

I see this project as the starting point for my long-term research goal of investigating the comorbidity between neuropsychiatric disorders and cardiometabolic diseases, and expanding knowledge and skills in longitudinal big data analysis and machine learning. Elucidating the effect of cardiovascular and metabolic disease, traumatic brain injury, sleep, depression, and physical and cognitive activity on dementia, cognitive aging, and brain health will be my priority during the fellowship. I received broad training in Clinical and Psychosocial Epidemiology during my master’s degree study in Graduate School of Medical Science at the University of Groningen, The Netherlands. At the same time, I have actively taken (summer)courses and seminar classes in applied longitudinal data analysis, mixed models for clustered data, group-based trajectory modeling, psychiatric epidemiology and machine learning.

I am excited about the opportunity to collaborate with CPBH investigators, participate in didactic sessions and mentored by you. Enclosed you will find my CV. Please let me know if I can provide additional information or materials required for my application. Thank you in advance for your time and consideration of my application. I look forward to hearing from you.

Yours sincerely,

Tesfa D. Habtewold