Chinese Longitudinal Healthy Longevity Study

The Chinese Longitudinal Healthy Longevity Study conducted its first basline survey in 1998 and entered its 9th wave of data collection in 2021.  Led by Professor Yi Zeng, PhD of Duke University and Peking University, the goals of the research are to discover the social, behavioral, environmental, and bio-medical factors and interactions that may influence healthy longevity and family happiness, as well as to provide data for academic research, and information for health and healthy aging policy analysis. 

Study Goals and Design

The first eight waves of the Chinese Longitudinal Healthy Longevity Study (CLHLS) were conducted in 1998-2018. The 9th wave is conducted in 2021 and extended as “The Chinese Longitudinal Healthy Longevity and Happy Family Study (CLHLS-HF), through adding several family-relevant questions in addition to CLHLS’ initial questionnaire which contained about one-third of the total number of questions. The PI of CLHLS-HF (1998-2021) and CLHLS-HF is Professor Yi Zeng of Peking University and Duke University). Our general goals are to discover the social, behavioral, environmental, and bio-medical factors and their interactions that may influence healthy longevity and family Happiness, as well as to provide data for academic research, and information for health and healthy aging policy analysis.

The baseline survey was conducted in 1998 and the follow-up surveys (with new recruitments to replace dead participants in most waves) were conducted in 2000, 2002, 2005, 2008-2009, 2011-2012, 2014, and 2017-2018 in randomly selected about half of the counties and city districts of 23 out of 31 Chinese provinces, municipalities and autonomous regions (Liaoning, Jilin, Heilongjiang, Hebei, Beijing, Tianjin, Shanxi, Shaanxi, Shanghai, Jiangsu, Zhejiang, Anhui, Fujian, Jiangxi, Shangdong, Henan, Hubei, Hunan, Guangdong, Guangxi, Sichuan, Chongqing, Hainan). The survey areas covered 985 million persons in the baseline year 1998 and 1,156 million persons in the census year 2010, about 84-85 percent of the total population of China. The 9th wave of CLHLS-HF in 2021 is substantially extended to cover 27 provinces, municipalities and autonomous regions in China, including four additional provinces of Guizhou, Yunnan, Ganshu and Ninxia.

In the 8 waves of the CLHLS conducted in 1998-2018, we have conducted face-to-face home-based 113 thousands interviews, including 19.5 thousand centenarians, 26.7 thousands nonagenarians, 29.7 thousands octogenarians, 25.5 thousands younger elders aged 65-79, and 11.3 thousands middle-age adults aged 35-64. Data on death dates/age and relatively detailed information of health status and care needs/costs etc. before dying for the 28.9 thousands elders aged 65-118 who died between waves were collected in interviews with a close family member of the deceased. All of the interviews, basic health exams and biomarkers samples collections are voluntary with standard consensus forms reviewed/signed by the participants (or their direct family members).

       Among the randomly selected survey sites of counties/city districts, CLHLS selected eight longevity areas (counties/cities), where the proportion of centenarians are exceptionally high, to conduct in-depth study with 3470, 2860, 2639 and 2786 elderly participants in the CLHLS 2008-2009, 2011-2012, 2014 and 2017-2018 waves. The CLHLS in-depth study in the 8 longevity areas conducted face-to-face interviews using the same questionnaire as that used in all other study sites,  plus home-based basic health exams by medical doctors/nurses and blood/urine sample collections from the participants, and biomarkers lab tests and analyses.

        Data collections of CLHLS have been coordinated by the Center for Healthy Aging and Development Studies of National School of Development at Peking University, and the survey field works were carried out through the nationwide survey/health service networks by Chinese Center for Scientific Research on Aging for the 1st, 2nd, 3rd and 4th waves in 1998-2005, and by China Center for Diseases Control and Prevention (CDC) for the 5th, 6th, 7th and 8th wave in 2008-2018. The survey field works of the 9th wave in 2021 are carried out by the nationwide survey/health service networks by China Population and Development Research Center for the nationwide surveys and by National Institute of Environmental Health of China CDC for the in-depth study sites of the 8 longevity areas.

        The seven waves of CLHLS in 1998-2014 were jointly supported by NIA/NIH (5R01AG023627; 2P01AG031719), China Natural Sciences Foundation (NSFC) (71233001, 71110107025), UNFPA, and other Chinese resources. The 8th wave of CLHLS in 2017-2018 was supported by NSFC (71490732), and NIA/NIH discontinued financial support to the 8th wave field work in China, while NIA/NIH continues support of the CLHLS research at Duke University.

Data and Dataset Access

     The questionnaire data collected provides information on family structure, living arrangements and proximity to children, activities of daily living (ADL), the capacity of physical performance (picking up a book from the floor; standing up from a chair; turning 360° without help), self-rated health, self-evaluation of life satisfaction, cognitive functioning, chronic disease prevalence, care needs and costs, participation in social activities, diet, smoking and drinking behaviors, psychological characteristics, economic resources, and care giving and family support among elderly respondents and their relatives. Information about the health status of the CLHLS participants who were interviewed in the previous wave but died before the current survey was collected by interviewing a close family member. Information provided consists of cause of death, chronic diseases, ADL before dying, frequency of hospitalization or instances of being bedridden from the last interview until death, whether bedridden before death, length of disability and suffering before death, etc.

       For the participants from the in-depth study sites of the 8 longevity areas, in addition to the questionnaire interview data, the CLHLS conducted lab tests of the following biomarkers using blood/urine samples collected from the voluntary participants: Routine blood tests: White Blood Cell Count, Lymphocyte count, Percentage of lymphocytes, Red Blood Cell Count, Hemoglobin, Erythrocyte  Hematocrit, Erythrocyte Mean Corpuscular Volume, Erythrocyte Mean Corpuscular Hemoglobin, Erythrocyte Mean Corpuscular Hemoglobin Concentration, Platelet Count, Mean Platelet Volume, Platelet Distribution Width, Plateletocrit; Plasma tests: Plasma albumin, Blood Urea Nitrogen, Total cholesterol, Plasma creatine, High-sensitive c reacitve protein,

Plasma glucose, Glycolated plasma protein, High-density lipoprotein cholesterol, Low-density lipoprotein cholesterol, Triglyceride, Urea acid, Superoxide dismutase, 25-oh-vitamind3, Malondialdehyde. Vitamin b12; Urine tests:  Urine microalbumin, Urine creatinine, Ualb/ucr ratio.

        The baseline, the cross-sectional and follow-up survey datasets and documents (questionnaires, users’ guides, etc.) of the eight waves of CLHLS conducted in 2000, 2002, 2005, 2008-2009, 2011-2012, 2014 and 2017-2018 are being distributed to the research community. Researchers can download the datasets free of charge from the following websites:

(1) https://opendata.pku.edu.cn; Peking University Open Access Research Database.

(2) https://www.icpsr.umich.edu/icpsrweb/NACDA/series/487; National Archive of Computerized Data on Aging (NACDA) sponsored by U.S. National Institute of Aging (NIA/NIH), Inter-university Consortium for Political and Social Research (ICPSR) at University of Michigan.

       As of October 15, 2021 according to incomplete statistics, there are 10,327 registered CLHLS data users (excluding their students and other group members), and they produced following publications using the CLHLS datasets:  

  • 17 books (five in English and twelve in Chinese).
  • 431 papers written in English, published in peer-reviewed journals outside of China. 
  • 731 papers written and published in peer-reviewed Chinese journals.
  • 99 Ph.D. dissertations successfully defended at Universities inside and outside of China.
  • 678 M.A. theses successfully defended at Universities inside or outside of China.

Sample Distributions of the 1998, 2000, 2002, 2005, 2008-2009, 2011-2012, 2014 and 2017-2018 Waves of the CLHLS

Sex & age

Surviving interviewees

Deceased interviewees

 

1998

2000

2002

2005

2008-2009

2011-2012

2014

2017-2018

Total

1998-2000

2000-2002

2002-2005

2005-2009

2008-2012

2011-2014

2014-2018

Total

Men

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

35-64

---

--

2,945

1,834

1,908

271

65

52

7,075

---

---

---

---

4

---

0

4

65-79

---

--

2,560

2,787

2,257

1,712

1,294

2,698

13,308

---

---

272

218

210

128

137

965

80-89

1,787

2,467

2,128

1,932

2,148

1,316

1,082

1,894

14,754

339

481

721

539

549

325

307

3,261

90-99

1,299

1,645

1,584

1,659

1,897

1,017

705

1577

11,375

574

543

855

880

988

543

395

4,778

100+

481

518

676

581

688

287

170

708

4,109

348

292

450

429

437

203

144

2,303

Total

3,567

4,630

9,893

8,793

8,898

4,603

3,316

6,921

50,621

1,261

1,316

2,298

2,066

2,188

1,199

983

11,311

Women

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

35-64

---

---

1,301

732

1,892

238

20

43

4,226

---

---

---

---

2

---

1

3

65-79

---

---

2,447

2,538

2,028

1,437

1,075

2,654

12,179

---

---

229

172

127

82

66

676

80-89

1,741

2,451

2,111

1,977

2,124

1,324

1,125

2,110

14,963

262

367

627

419

399

251

220

2,545

90-99

1,714

2,167

2,163

2,293

2,699

1,416

949

1977

15,370

612

677

1,085

1,050

1,204

655

452

5,735

100+

1,937

1,913

2,513

2,216

2,725

1,170

707

2169

15,350

1,213

930

1,635

1,502

1,722

692

504

8,198

Total

5,392

6,531

10,535

9,756

11,468

5,585

3,876

8,945

62,088

2,087

1,974

3,576

3,143

3,454

1,680

1,243

17,157

Two sex

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

35-64

---

---

4,246

2,566

3,800

509

85

95

11,301

---

---

---

---

6

---

1

7

65-79

---

---

5,007

5,325

4,285

3,149

2,369

5,352

25,487

---

---

501

390

337

210

203

1641

80-89

3,528

4,918

4,239

3,909

4,272

2,640

2,207

4,004

29,717

601

848

1,348

958

948

576

527

5,806

90-99

3,013

3,812

3,747

3,952

4,596

2,433

1,654

3,546

26,745

1,186

1,220

1,940

1,930

2,192

1,198

847

10,513

100+

2,418

2,431

3,189

2,797

3,413

1,457

877

2877

19,459

1,561

1,222

2,085

1,931

2,159

895

648

10,501

Total

8,959

11,161

20,428

18,549

20,366

10,188

7,192

15,874

112,709

3,348

3,290

5,874

5,209

5,642

2,879

2,226

28,468