Longitudinal Ageing Study in India (LASI)

The Longitudinal Ageing Study in India (LASI) is India's first and largest nationally representative panel survey dedicated to the population aged 45 years and older, together with their spouses irrespective of age. It was commissioned by the Ministry of Health and Family Welfare (MoHFW) and executed by the International Institute for Population Sciences (IIPS), Mumbai, in scientific collaboration with the Harvard T.H. Chan School of Public Health and the University of Southern California. The study draws methodological and financial support from the National Institute on Aging (NIA) of the United States and the United Nations Population Fund (UNFPA). LASI belongs to a global family of harmonised ageing surveys modelled on the U.S. Health and Retirement Study (HRS), enabling cross-national comparison with the English Longitudinal Study of Ageing (ELSA), the Survey of Health, Ageing and Retirement in Europe (SHARE), and the China Health and Retirement Longitudinal Study (CHARLS). Its statutory rationale lies in the data gap identified by the National Policy on Older Persons (1999) and the Maintenance and Welfare of Parents and Senior Citizens Act, 2007, both of which presupposed evidence that did not then exist at scale.

The survey's procedural architecture is built on a multistage stratified area probability cluster sampling design, drawing respondents from all 28 states and 8 union territories (excluding only Sikkim in the first wave). The Wave 1 sample comprised 72,250 individuals aged 45 and above across roughly 35,000 households, making it among the largest ageing surveys conducted globally. Data collection proceeds through computer-assisted personal interviewing (CAPI), combining a household questionnaire with an individual questionnaire that captures demographic characteristics, household economy, chronic and acute morbidity, functional health, mental health, healthcare utilisation, social networks, and subjective well-being. The defining feature is its longitudinal design: the same respondents are re-interviewed at successive waves approximately every two to three years, permitting researchers to observe transitions—into widowhood, disability, institutional care, or labour-force exit—rather than mere snapshots that a cross-sectional instrument would yield.

A distinguishing methodological strength is the integration of self-reported data with direct biomarker measurement, a component absent from most Indian household surveys. Trained field investigators record anthropometric measures (height, weight, waist and hip circumference), blood pressure, lung function via spirometry, grip strength, and timed walk and balance tests, alongside the collection of dried blood spots for assays of haemoglobin, HbA1c, lipid profile, and other indicators. This allows verification of self-reported conditions such as hypertension and diabetes and uncovers undiagnosed disease burden. The survey also administers cognitive assessment modules adapted from HRS to screen for dementia and cognitive decline, feeding into a dedicated sub-study, the LASI-Diagnostic Assessment of Dementia (LASI-DAD), which provides nationally representative estimates of dementia prevalence among older Indians.

LASI Wave 1 fieldwork was conducted between 2017 and 2019, and the comprehensive India Report was released in January 2021 by the MoHFW. Its findings carry direct policy weight: it documented that the population aged 60 and above stood near 138 million and projected it to rise sharply through 2050, that a substantial share of older persons report multimorbidity, and that a majority of the elderly remain economically dependent with limited pension or insurance coverage. The report was used to inform programmes such as the National Programme for the Health Care of the Elderly (NPHCE) and discussions around expanding the Ayushman Bharat and old-age pension architecture. Subsequent waves continue under IIPS stewardship, with state-level fact sheets and the LASI-DAD findings on dementia prevalence drawing attention from the Niti Aayog and geriatric clinicians.

LASI must be distinguished from adjacent Indian data instruments. Unlike the National Family Health Survey (NFHS), which is cross-sectional and centred on maternal, child, and reproductive health across the general population, LASI is panel-based and age-focused on 45-plus cohorts. It differs from the National Sample Survey (NSS) consumption and health rounds, which capture expenditure and morbidity without re-interviewing the same individuals over time, and from the decennial Census, which enumerates the whole population but lacks depth on health, cognition, and biomarkers. Crucially, LASI's panel character separates it from the Building a Knowledge Base on Population Ageing in India (BKPAI) study of 2011, a smaller cross-sectional precursor covering seven states, which LASI superseded in scope and rigour.

Controversies and limitations attend any survey of this magnitude. Self-reported morbidity in older populations is subject to recall bias and the well-documented socioeconomic gradient in disease awareness, which biomarkers only partially correct. Panel attrition through mortality and migration threatens the representativeness of later waves and complicates weighting. Field collection of blood spots and spirometry raises consent, quality-control, and biosafety challenges across heterogeneous rural settings, and the COVID-19 pandemic disrupted the cadence of follow-up fieldwork after 2020. Comparability with HRS-family surveys, while a strength, also imports instruments designed for Western contexts that require careful cultural adaptation, particularly in the cognition and mental-health modules.

For the working practitioner—whether a UPSC aspirant addressing General Studies Paper I demography questions, a desk officer drafting elderly-welfare policy, or a researcher modelling India's old-age dependency ratio—LASI is the authoritative empirical foundation on Indian ageing. It supplies the evidence base for anticipating the fiscal pressures of a greying population, designing pension and long-term-care systems, and benchmarking India against comparator economies. Mastery of LASI's design, headline findings, and institutional lineage allows the professional to ground arguments about demographic transition in data rather than assertion, and to anticipate the policy debates that India's accelerating population ageing will force onto the agenda over the coming decades.