Dr. Jonas S Sundarakumar

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Biosketch

Dr. Jonas is a National Board-certified Psychiatrist, who completed his MBBS and Post-graduate Diploma in Psychiatry (DPM) from Christian Medical College, Vellore, India. He further went on to obtain his MRCPsych from the Royal College of Psychiatrists, UK, and his DNB(Psych) from the National Board of Examinations, New Delhi, India. Being an experienced clinician with a keen interest in research, he transitioned to a full-time research career when he joined CBR in 2019.

Research

Identifying risk and protective factors for dementia through large-scale, prospective aging cohort studies:

In India, increasing lifespan and decreasing fertility rates have resulted in a growing number of older persons. By 2050, people over 60 years of age are predicted to constitute 19.1% of the total population. This ageing of the population is expected to be accompanied by a dramatic increase in the prevalence of dementia. Dementia is a syndrome that presents as impairment of mental processes, such as memory, thinking, reasoning and judgement, and thus seriously impairs an individual’s ability to perform functions of daily living. The syndrome is typically caused by a group of progressive, neurodegenerative brain disorders that occur in older age. The cost of care of people with dementia is enormous, at both the family and societal level.

As clinician who well understands the devastating impact of dementia on patients and their caregivers, Dr. Jonas combines his clinical perspective with his research experience and works as part of CBR’s unique, multidisciplinary research environment, to address the global health problem of dementia. His research is primarily aimed at studying the aging brain, particularly in pathological aging and thereby, understanding neurodegenerative disorders, such as dementia. He focuses on identifying risk and protective factors for dementia in the Indian population by carrying out large-scale human studies, wherein aging adults from rural and urban India are studied longitudinally over a long period of time, using multi-modal clinical, cognitive, biochemical measurements and brain MRI. This would enable tracking the differential cognitive trajectories of normal and pathological aging, and thereby, identify risk and protective factors for dementia.

He leads the efforts for the large-scale population-based, prospective, aging, cohort study in rural India conducted by CBR (Srinivaspura Aging NeuroSenescence and COGnition, SANSCOG study) and is also involved in the other parallel study in urban India (Tata Longitudinal Study of Aging, TLSA). The valuable insights gained from these studies, will further contribute to developing appropriate interventions that can help in preventing, delaying the onset, or mitigating the course of dementia. He is also interested in understanding the neuropsychological impact of COVID-19 including the effect on modifiable risk factors of dementia. He is also part of international scientific collaborations / consortia, such as the CNS-SARS-CoV2 consortium, Worldwide FINGERS network and Alzheimer’s Disease Data Initiative (ADDI).

People

Shruti Pandey

PhD student

Shruti is a joint Ph.D. student under the co-supervision of Dr. Jonas Sundarakumar and is pursuing a clinical-basic science collaborative research study on the effect of diabetes on changes in cognition in aging rural and urban Indians.

Dr. Sumedha Mitra

PhD student

Dr. Sumedha Mitra is a doctoral student and public health researcher with an under graduation in Dentistry from Manipal College of Dental Sciences, Mangalore. She completed her Master`s in Public Health with a specialisation in Epidemiology from PSPH, Manipal alongside collaborative foundations coursework in Global Health from Maastricht University, Netherlands. Her dissertation comprised of an occupational health oriented mixed-methods study on a cohort of night shift workers. Her prior experience spans across clinical, research and public health domains, at organisations including Indian Council of Medical Research (ICMR – NIOH), Indian Institute of Science (IISc- CNI), National Health Mission (NHM), MuSigma and Swasti Health Catalysts. As a doctoral student at CBR, she is currently working on an interdisciplinary study to explore the role of certain metabolic conditions and sleep in the development of cognitive impairments within rural and urban cohorts in India.

Priya Chatterjee

PhD student

Priya Chatterjee received her Bachelor’s and Master’s in Zoology from Barasat Govt. College, West Bengal State University. She is interested in understanding the role of various risk and protective factors associated with the development of dementia. Currently, she is studying the association between abnormal lipid metabolism and cognitive functioning in community dwelling healthy adults to evaluate the role of dyslipidemia as a modifiable risk factor contributing towards cognitive decline.

Former lab members

Dr. Ramya Burra

Post-doctoral Fellow

Dr. Pooja Rai

Post-doctoral Fellow

Raghav prasad

Research Intern

Sakshi Arora

Research Assistant

Hitesh Pradhan

Research Assistant

Pravin Sahadevan

Research intern (CBRAIN internship program)

Shilna Azhuvalappil

Research Intern

Dr. V.L. Remruatpuii

Research Intern

Aishwarya Hiremath

Project Associate

Pradipto Mondal

Research Intern

David Yao

Research Intern

Aman Bhonsale

Research intern (MBBS/MPH Research Internship Program, IISc)

Suhrud Panchawagh

Research intern (CBRAIN internship program)

Publications

Mitra S, Sagiraju M, Pradhan H, Yao D, Pinto JM, Sundarakumar JS*, SANSCOG Study Team. The Cognitive Toll of Household Air Pollution: Cross-sectional Associations between Polluting Cooking Fuel Use, Cognitive Functions and Brain MRI in a Rural Aging Population from Karnataka, India. The Lancet Regional Health – Southeast Asia. 2025 (In Press).

Chakraborthy S, Subramanian K, Rajesh A, Majumder R, Rupanagudi KV, Mensegere AL, TLSA Study Team, Issac TG, SANSCOG Study Team, Sundarakumar JS, Kahali B*. Genetic architecture of cardiometabolic traits and cognition in the Indian population: Deciphering their causal interrelationships. Alzheimer’s & Dementia. 2025 (In Press).

Chatterjee P, Arora S, Rai P, Diwakar L, Issac TG, Sundarakumar JS*. Rural-Urban Differences in Lipid Abnormalities among Middle-Aged and Older Indians. BMC Public Health (In Press).

Sundarakumar JS*, Sahadevan P, Hiremath A, Rai P. Poorer performance on physical frailty-related parameters is associated with depression among older rural Indians. Scientific Reports. 2025 May 23;15(1):18015. doi: 10.1038/s41598-024-83175-z.PMID: 40410182.

Rai P, Sundarakumar JS*. Association between social connectedness and mild cognitive impairment: A case-control study in aging rural Indians. Journal of Alzheimer’s Disease Reports. 2025;9. doi:10.1177/25424823251336115.PMID: 40421105.

Menesgere A, Annajigowda HH, Singh S, Sunny AS, Sundarakumar JS, Issac TG*. Handgrip strength as a biomarker for cognitive decline and brain atrophy in older adults. Asian Journal of Psychiatry. 2025 Apr 16;108:104506. doi: 10.1016/j.ajp.2025.104506. Epub ahead of print.PMID: 40273801.

Shivanna SH, Arvind P, Mensegere A, Jessy SA, Sundarakumar J, Issac TG*. Recruitment and Retention Strategies Adopted in an Indian Urban Longitudinal Study of Aging. Indian Journal of Public Health. 2025 Jan 1;69(1):130-132. doi: 10.4103/ijph.ijph_1378_23. Epub 2025 Mar 21.PMID: 40214335.

Menon AJ, Selva M, Sandhya G, Singh S, Abhishek ML, Stezin A, Sundarakumar JS, Diwakar L, Issac TG*. Understanding the link between insulin resistance and cognition: a cross-sectional study conducted in an urban, South Indian cohort. Acta Diabetologica. 2025 Mar 13. doi: 10.1007/s00592-025-02483-6. Epub ahead of print.PMID: 40080198.

Monisha S, Roy D, Menon AJ, G S, Gupta A, Basavaraju N, Singh S, Sundarakumar JS, Kommaddi R, Issac TG*. Exploring predementia: Understanding the characteristics of subjective cognitive decline plus from India. Journal of Alzheimer’s Disease. 2025 Feb;103(3):966-973. doi: 10.1177/13872877241307344. Epub 2025 Jan 21PMID: 39834257.

Roy D, Monisha S, Sandhya G, Sundarakumar JS, Issac TG*. Prevalence of Subjective Cognitive Decline and Mild Cognitive Impairment in Rural Versus Urban Population: Insights from India. Annals of Indian Academy of Neurology. 2025 Jan 6. doi:10.4103/aian.aian_676_24.

Rai P, Sahadevan P, Issac TG, Sundarakumar JS*. Decomposing rural-urban differences in depression prevalence: a cross-sectional analysis of two community-based southern Indian cohorts. BMJ Public Health. 2024;2:e000760. doi:10.1136/bmjph-2023-00076.

Jessy AS, Sandhya G, Monisha S, Sundarakumar JS, Stezin A, Issac TG*. Prevalence of hypothyroidism in older adults and its association with cognition: a cross-sectional study from a South Indian ageing urban cohort. Brain Communications. 2024 Dec 5;6(6):fcae391. doi: 10.1093/braincomms/fcae391.PMID: 39659976

Tomkinson GR*, Lang JJ, Rubín L, McGrath R, Gower B, Boyle T, Klug MG, Mayhew AJ, Blake HT, Ortega FB, Cadenas-Sanchez C, Magnussen CG, Fraser BJ, Kidokoro T, Liu Y, Christensen K, Leong DP; iGRIPS (international handGRIP Strength) group. International norms for adult handgrip strength: A systematic review of data on 2.4 million adults aged 20 to 100+ years from 69 countries and regions. Journal of Sport and Health Science. 2024 Nov 22:101014. doi: 10.1016/j.jshs.2024.101014. Epub ahead of print.PMID: 39647778.

Rai P, Sundarakumar JS*. Association between social networks and cognition among middle-aged and older adults in rural India. Neuropsychology. 2024 Nov;38(8):740-748. doi: 10.1037/neu0000971PMID: 39480352.

Mallikarjun DN, Malo PK, Mensegere A, Partha A, Sundarakumar JS, Issac TG, Diwakar L*, TLSA and SANSCOG study teams. Comparison of homocysteine, vitamin B12 and folic acid between rural and urban ageing Indians and its association with mild cognitive impairment and cardiovascular risk factors: a cross-sectional analysis. Brain Communications. 2024 Oct 15;6(5):fcae343. doi: 10.1093/braincomms/fcae343PMID: 39411243.

Menesgere A, Singh S, Stezin A, Sundarakumar J, Issac T*. The impact of social isolation on cognitive performance and brain volumes among the urban older Indian cohort. Asian Journal of Psychiatry. 2024 Sep 27;102:104258. doi: 10.1016/j.ajp.2024.104258. Epub ahead of print.PMID: 39369644.

Mallikarjun DN, Jain S, Malo PK, Kahali B, Sundarakumar JS, Diwakar L, Ravindranath V. Distribution of biochemical and hematological parameters in an aging population from southern India – A cross sectional analysis. Annals of Clinical Biochemistry. 2024 Jul 25:45632241267905. doi: 10.1177/00045632241267905. Epub ahead of print.PMID: 39054723.

Azhuvalappil S, Prasad R, Sahadevan P, Chatterjee P, Pradhan H, Rai P, Gupta A, Kommaddi RP, Issac TG, Sundarakumar JS*. Association between APOE genotypes and Metabolic Syndrome in an Older Urban Indian Population. Metabolism Open. 2024;23:100301. doi: https://doi.org/10.1016/j.metop.2024.100301.PMID: 39148663.

Mensegere A, Singh S, Stezin A, Sundarakumar JS, Issac TG*. Effect of early menopause on cognition and brain morphology in an Urban Indian Cohort. Alzheimer’s and Dementia. 2024 Jul 1. doi: 10.1002/alz.14069. Epub ahead of print.PMID: 38946683.

Rai P, Sundarakumar JS*. Shorter sleep duration and lesser sleep efficiency are associated with poorer memory functions among non-demented, middle- and older-aged rural Indians. SLEEP Advances. 2024;5(1). doi: 10.1093/sleepadvances/zpae038. . doi: 10.1093/sleepadvances/zpae038.PMID: 39011420.

Arora S, Sahadevan P, Sundarakumar JS*. Association of Sleep Quality with Physical and Psychological Health Indicators among Overweight and Obese Rural Indians. Sleep Medicine: X. 2024 May 3;7:100112. doi: 10.1016/j.sleepx.2024.100112.PMCID: PMC11127281.PMID: 38800099.

Arvind P, Mensegere AL, Malo PK, Sundarakumar JS, Issac TG*. Assessment of Cognitive Status in Geriatric Individuals with a History of COVID-19 Exposure. Gerontology & Geriatrics Studies. Published online on April 12, 2024. doi: 10.31031/GGS.2024.09.000701.

Azhuvalappil S, Prasad R, Sahadevan P, Pradhan H, Rai P, Sundarakumar JS*. Sex-specific differences in the association between APOE genotype and metabolic syndrome among middle-aged and older rural Indians. Metabolism Open. 2024 Apr 9;22:100281. doi: 10.1016/j.metop.2024.100281. PMCID: PMC11035107.PMID: 38659620

Rai P, Sahadevan P, Mensegere AL, Issac TG, Muniz-Terrera G, Sundarakumar JS*. Rural-urban disparities in the diagnosis and treatment of hypertension and diabetes among aging Indians. Alzheimer’s and Dementia. 2024 Apr;20(4):2943-2951. doi: 10.1002/alz.13771. Epub 2024 Mar 9. PMCID: PMC11032561.PMID: 38460118.

Hiremath A, Mitra S, Rai P, Shahul SK, Mensegere AM, Issac TG, Sundarakumar JS*. Applications of geospatial mapping in the assessment of environmental risk factors for dementia. Annals of Neurosciences. January 18, 2024 (Online First). doi: 10.1177/09727531231222322.Epub ahead of print.PMID: 39544653.

Rai P, Sundarakumar JS*, Basavaraju N, Kommaddi RP, Issac TG. Association between ApoE ?4 genotype and attentional function in non-demented, middle-aged, and older adults from rural India. Journal of Neurosciences in Rural Practice. 2024 Jan-Mar;15(1):117-125. doi: 10.25259/JNRP_272_2023. Epub 2024 Jan 9. PMCID: PMC10927062. PMID: 38476424

Rai P, Sundarakumar JS*. The role of gender in the relationship between social engagement and health outcomes. SSM Population Health. 2023 Dec 29;25:101554. doi: 10.1016/j.ssmph.2023.101554. PMCID: PMC10801295. PMID: 38260721

Mensegere AL, Sundarakumar JS*, Diwakar L, Issac TG and SANSCOG Study Team (2023). Relationship between Framingham Cardiovascular Risk Score and cognitive performance among ageing rural Indian participants: a cross-sectional analysis. BMJ Open. 2023 Nov 10;13(11):e074977. doi: 10.1136/bmjopen-2023-074977. PMCID: PMC10649489.PMID: 37949620.

Menon AJ, Malo PK, Jain S, Gandhi S, Sundarakumar JS, Rai P, Issac TG. Association between multilingualism and cognitive performance among older adults in rural southern India. Journal of Neurosciences in Rural Practice. 2024 Jan-Mar;15(1):81-85. doi: 10.25259/JNRP_376_2023. Epub 2023 Oct 30. PMCID: PMC10927057.PMID: 38476421.

Menon AJ, Gandhi S, Varadharajan A, Rai P, Sundarakumar JS, Issac TG*. Particulate matter 2.5- Muddling the healthy brain. Journal of Psychiatry Spectrum. 2(2):p129-130, Jul–Dec 2023. doi: 4103/jopsys.jopsys_7_23.

Sundarakumar JS*, Mensegere AL, Malo PK, Ravindranath V, SANSCOG Collaborators. Impact of the COVID-19 pandemic on some modifiable risk factors of dementia in an aging, rural Indian population. Frontiers in Psychiatry. 2023 May 19;14:954557. doi: 10.3389/fpsyt.2023.954557. PMCID: PMC10237042.PMID: 37275968.

Sundarakumar JS, Menesgere AL, Jain S, Hameed SKS, SANSCOG & TLSA Study Teams, Ravindranath V*. Prevalence of neuropsychiatric conditions and cognitive impairment in two parallel, aging study cohorts from rural and urban India. Alzheimer’s & Dementia. 2023 Jun;19(6):2469-2478. doi: 10.1002/alz.12741. Epub 2022 Dec 26.PMID: 36573020.

Sundarakumar JS, Hameed SKS, Dilip B, Deepak S, Kumar BRV, Ravindranath V*. Approaches to engage an aging, rural cohort in southern India during the COVID-19 crisis and the psychological impact of COVID-19 in this cohort. Alzheimer’s & Dementia. 2023 Jun;19(6):2460-2468. doi: 10.1002/alz.12726. Epub 2022 Dec 9. PMCID: PMC9878015.PMID: 36468341.

Menesgere A, Sundarakumar JS, Shahul Hameed SK, SANSCOG & TLSA Study Teams, Ravindranath V*. Comparison of risk factors for dementia among rural and urban elderly adults-data from two cohort studies in India. Alzheimer’s & Dementia. 2023 Jun;19(6):2443-2449. doi: 10.1002/alz.12715. Epub 2022 Dec 22.PMID: 36548115.

Ravindranath V*; SANSCOG Study Team. Srinivaspura Aging, Neuro Senescence and COGnition (SANSCOG) study: Study protocol. Alzheimer’s & Dementia. 2023 Jun;19(6):2450-2459. doi: 10.1002/alz.12722. Epub 2022 Dec 28.PMID: 36577090.

Sundarakumar JS*, Menesgere AL, Hameed SKS, SANSCOG & TLSA Study Teams, Ravindranath V. Depression and anxiety during the first and second waves of the COVID-19 pandemic in two large, prospective, aging cohorts in rural and urban India. Health Science Reports. 2022 Nov 8;5(6):e901. doi: 10.1002/hsr2.901. PMCID: PMC9642812.PMID: 36381404.

de Erausquin GA*, Snyder H, Brugha TS, Seshadri S, Carrillo M, Sagar R, Huang Y, Newton C, Tartaglia C, Teunissen C, Håkanson K, Akinyemi R, Prasad K, D’Avossa G, Gonzalez-Aleman G, Hosseini A, Vavougios GD, Sachdev P, Bankart J, Mors NPO, Lipton R, Katz M, Fox PT, Katshu MZ, Iyengar MS, Weinstein G, Sohrabi HR, Jenkins R, Stein DJ, Hugon J, Mavreas V, Blangero J, Cruchaga C, Krishna M, Wadoo O, Becerra R, Zwir I, Longstreth WT, Kroenenberg G, Edison P, Mukaetova-Ladinska E, Staufenberg E, Figueredo-Aguiar M, Yécora A, Vaca F, Zamponi HP, Re VL, Majid A, Sundarakumar J, Gonzalez HM, Geerlings MI, Skoog I, Salmoiraghi A, Boneschi FM, Patel VN, Santos JM, Arroyo GR, Moreno AC, Felix P, Gallo C, Arai H, Yamada M, Iwatsubo T, Sharma M, Chakraborty N, Ferreccio C, Akena D, Brayne C, Maestre G, Blangero SW, Brusco LI, Siddarth P, Hughes TM, Zuñiga AR, Kambeitz J, Laza AR, Allen N, Panos S, Merrill D, Ibáñez A, Tsuang D, Valishvili N, Shrestha S, Wang S, Padma V, Anstey KJ, Ravindrdanath V, Blennow K, Mullins P, ?ojek E, Pria A, Mosley TH, Gowland P, Girard TD, Bowtell R, Vahidy FS. Chronic neuropsychiatric sequelae of SARS-CoV-2: Protocol and methods from the Alzheimer’s Association Global Consortium. Alzheimer’s & Dementia: Translational Research & Clinical Interventions. 2022 Sep 22;8(1):e12348. doi: 10.1002/trc2.12348. PMCID: PMC9494609.PMID: 36185993.

Sundarakumar JS*, Stezin A, Menesgere AL, Ravindranath V, SANSCOG and TLSA Collaborators. Rural-urban and gender differences in metabolic syndrome in the aging population from southern India: Two parallel, prospective cohort studies. EClinicalMedicine. 2022 Apr 19;47:101395. doi: 10.1016/j.eclinm.2022.101395. PMCID: PMC9044001.PMID: 35497067.

Sundarakumar JS*, Raviteja KV, Muniz-Terrera G, Ravindranath V. Normative data for three physical frailty parameters in an aging, rural Indian population. Health Science Reports. 2022 Mar 22;5(2):e567. doi: 10.1002/hsr2.567.PMCID: PMC8938919.PMID: 35356805.

Ravindranath V*, Sundarakumar JS. Changing demography and the challenge of dementia in India. Nature Reviews: Neurology. 2021 Dec;17(12):747-758. doi: 10.1038/s41582-021-00565-x. Epub 2021 Oct 18. PMCID: PMC8522537.PMID: 34663985

Sundarakumar JS, Shahul Hameed SK, SANSCOG Study Team, Ravindranath V*. Burden of Vitamin D, Vitamin B12 and Folic Acid Deficiencies in an Aging, Rural Indian Community. Frontiers in Public Health. 2021;9:707036. Published 2021 Sep 3. doi:10.3389/fpubh.2021.707036. PMCID: PMC8446357.PMID: 34540786.

Baheshree RD, Jonas SS*. Dysphagia in a psychotic patient: Diagnostic challenges and a systematic management approach. Indian Journal of Psychiatry. 2012 Jul;54(3):280-2. doi: 10.4103/0019-5545.102464. PMCID: PMC3512371.PMID: 23226858.

Suganthan JS, Rajkumar AP*, Jagannath C, Pulimood SA, Jacob KS. Delusional parasitosis over dermatological morbidity: diagnostic and therapeutic challenges. Tropical Doctor. 2009 Jan;39(1):49-50. doi: 10.1258/td.2008.080021.PMID:19211429.

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