# Qi Sun
**Qi Sun** (孙齐) is a physician-scientist in nutrition and chronic-disease epidemiology, known for research linking diet, environmental exposures, and biomarkers to type 2 diabetes and cardiovascular disease.[1](https://hsph.harvard.edu/profile/qi-sun/) He is Associate Professor of Medicine at [Brigham and Women's Hospital](https://www.edgepedia.org/brigham-and-womens-hospital) and Associate Professor in the Departments of Nutrition and [Epidemiology](https://www.edgepedia.org/epidemiology) at the Harvard T.H. Chan School of Public Health, where he directs the Nutritional Biomarker Laboratory.[2](https://connects.catalyst.harvard.edu/Profiles/profile/1237717) His program integrates omics technologies with nutritional epidemiology to identify biomarkers of diet and environmental exposures that predict excess weight gain, type 2 diabetes, and cardiovascular disease.[1](https://hsph.harvard.edu/profile/qi-sun/)
| Key fact | Detail |
|---|---|
| Field | Nutrition and chronic-disease epidemiology; environmental health |
| Positions | Associate Professor of Medicine, Brigham and Women's Hospital; Associate Professor of Nutrition and Epidemiology, Harvard T.H. Chan School of Public Health; Director, Nutritional Biomarker Laboratory[2](https://connects.catalyst.harvard.edu/Profiles/profile/1237717) |
| Training | MD, Beijing Medical University, 1999; MMS, Beijing University Health Science Center, 2002; ScD in Nutrition and Epidemiology, Harvard School of Public Health, 2007[3](https://synapsesocial.com/authors/69dc1f637e7b04fa41f6ecdf) |
| Signature work | "Smoking Cessation, Weight Change, Type 2 Diabetes, and Mortality," *New England Journal of Medicine*, 2018[4](https://www.nejm.org/doi/full/10.1056/NEJMoa1803626) |
| Main cohorts | Nurses' Health Studies I and II; Health Professionals Follow-up Study; POUNDS-Lost; CARDIA[5](https://hub.nutritionsociety.org/content/plant-based-diets-quality/) • [6](https://hsph.harvard.edu/environmental-health-niehs/news/meet-our-members-qi-sun-md-scd/) |
| Major grant | NIH R01DK120870, "Food-Based Biomarkers, Diet Quality, and Cardiometabolic Health," $518,700, April 15, 2019 to March 31, 2025[7](https://explore.openalex.org/awards/g5962171751) |
| Awards | Trudy Bush Fellowship (2008) and Mark Bieber Award (2013), American Heart Association[1](https://hsph.harvard.edu/profile/qi-sun/) |
## Education and career
Sun received his MD in Maternal and [Child Health](https://www.edgepedia.org/child-health) from Beijing Medical University in 1999 and a Master of Medical Science in Social Medicine and Health Service Management from Beijing University Health Science Center in 2002; he was a cum laude graduate of [Peking University](https://www.edgepedia.org/peking-university) in 2002.[1](https://hsph.harvard.edu/profile/qi-sun/) • [3](https://synapsesocial.com/authors/69dc1f637e7b04fa41f6ecdf) He earned his ScD in [Nutrition](https://www.edgepedia.org/nutrition) and Epidemiology from the Harvard School of Public Health in 2007 and has remained at Harvard and Brigham and Women's Hospital since.[3](https://synapsesocial.com/authors/69dc1f637e7b04fa41f6ecdf) • [8](https://cdnm.bwh.harvard.edu/qi-sun-md-scd/)
At Brigham and Women's Channing Division of Network Medicine, his listed research areas are nutrition, epidemiology, environmental pollutants, biomarkers, microbiome, and metabolomics.[8](https://cdnm.bwh.harvard.edu/qi-sun-md-scd/) He directs the Nutritional Biomarker Laboratory and is a Faculty Affiliate in the Department of Epidemiology.[2](https://connects.catalyst.harvard.edu/Profiles/profile/1237717) He has been principal investigator or co-PI on four concurrent R01 grants focused primarily on diabetes.[9](https://catalyst.harvard.edu/news/article/five-questions-with-qi-sun/)
## Smoking cessation, weight change and cardiometabolic risk
One line of his work addressed a clinical worry: whether weight gain after quitting smoking erases the benefits of quitting. In a 2018 *New England Journal of Medicine* analysis pooling three US cohorts, the risk of type 2 diabetes was higher among recent quitters (2 to 6 years since cessation) than among current smokers, with a hazard ratio (statistical measure comparing disease risk between groups over time) of 1.22 (95% CI 1.12 to 1.32); the risk peaked 5 to 7 years after quitting and then gradually declined. That temporary increase was proportional to weight gain and absent among quitters who gained no weight (P<0.001 for interaction).[4](https://www.nejm.org/doi/full/10.1056/NEJMoa1803626)
Mortality told the opposite story: hazard ratios for cardiovascular death among recent quitters, compared with current smokers, were roughly 0.55 without weight gain, about 0.4 with a 0.1 to 5.0 kg gain, about 0.2 with a 5.1 to 10.0 kg gain, and about 0.25 with more than 10.0 kg of gain. The study concluded that weight gain after cessation did not mitigate the benefits of quitting on cardiovascular and all-cause mortality.[4](https://www.nejm.org/doi/full/10.1056/NEJMoa1803626) Sun summarized in interview that long-term quitters showed a steady reduction in cardiovascular and other-cause mortality independent of how much weight they gained.[10](https://www.abc.net.au/listen/programs/healthreport/smoking-weight-gain-and-type-2-diabetes/10194240)
A 2020 follow-up in *The Lancet Diabetes & Endocrinology* examined people already living with type 2 diabetes, using [Nurses' Health Study](https://www.edgepedia.org/nurses-health-study) (1976–2014) and Health Professionals Follow-up Study (1986–2014) data: 10,809 people entered the incident cardiovascular disease analysis and 9,688 the mortality analysis. Recent quitters without weight gain had significantly lower cardiovascular disease risk than continuing smokers (HR 0.77, 95% CI 0.62 to 0.95), longer-term quitters had HR 0.72 (0.61 to 0.84), and weight gain within 6 years of cessation did not attenuate the inverse relation between long-term cessation and all-cause mortality.[11](https://pubmed.ncbi.nlm.nih.gov/31924561/)
## Diet and type 2 diabetes
A 2012 BMJ meta-analysis and systematic review, [White rice consumption and risk of type 2 diabetes: meta-analysis and systematic review](https://doi.org/10.1136/bmj.e1454), with Sun as last author pooled 13,284 incident type 2 diabetes cases among 352,384 participants followed 4 to 22 years. Each additional daily serving of white rice was associated with a relative risk of type 2 diabetes of 1.11 (95% CI 1.08 to 1.14). The association was stronger in Asian populations, where average intake runs three to four servings per day (pooled RR 1.55, 95% CI 1.20 to 2.01, highest versus lowest intake), than in Western populations, where intake is one to two servings per week (RR 1.12, 0.94 to 1.33).[13](https://www.bmj.com/content/344/bmj.e1454)
A December 2023 *JAMA Network Open* study examined low-carbohydrate diet macronutrient quality and weight change.[14](https://pmc.ncbi.nlm.nih.gov/articles/PMC12635889/) A December 2025 *Diabetes Care* cohort study followed 199,006 US adults from the Nurses' Health Study, NHSII, and the Health Professionals Follow-up Study for over 30 years, documenting 20,452 incident type 2 diabetes cases during 4,987,761 person-years. An animal-based low-carbohydrate diet was associated with higher risk (HR 1.39, 95% CI 1.32 to 1.45), while a healthy low-carbohydrate diet that deemphasized refined carbohydrates was associated with 16% lower risk (HR 0.84, 0.81 to 0.88).[15](https://www.ovid.com/journals/dcar/pdf/10.2337/dc25-1401~low-carbohydrate-diets-of-varying-macronutrient-quality-and)
## Environmental health and nutritional biomarkers
Sun entered environmental epidemiology about a decade before his center interview by co-leading, as co-PI, an NIEHS-funded grant evaluating persistent organic pollutants, including PFAS, in relation to diabetes risk in the Nurses' Health Study cohorts.[6](https://hsph.harvard.edu/environmental-health-niehs/news/meet-our-members-qi-sun-md-scd/) According to the Harvard NIEHS Center's member profile, in the POUNDS-Lost weight-loss trial he found that PFOA levels were associated with detrimental apolipoprotein C-III levels, and he leads a Nurses' Health Study and Health Professionals Follow-up Study project on PFAS, blood lipoprotein and apolipoprotein profiles, and coronary heart disease risk.[6](https://hsph.harvard.edu/environmental-health-niehs/news/meet-our-members-qi-sun-md-scd/) With US CDC scientists he is measuring PAHs and HAAs, two groups of chemicals generated by high-temperature cooking of animal products, in urine from the POUNDS-Lost trial, Nurses' Health Study II, and the CARDIA Study, supported by an NIEHS R01 that has funded his obesogens research for the past seven years.[6](https://hsph.harvard.edu/environmental-health-niehs/news/meet-our-members-qi-sun-md-scd/) In 2021 he received Harvard Catalyst pilot funding through its Everyday Exposures – Toxins & Health program to test whether PFAS raise heart disease risk in Nurses' Health Study I and II and the Health Professionals Follow-up Study.[9](https://catalyst.harvard.edu/news/article/five-questions-with-qi-sun/)
His biomarker discoveries include very-long-chain saturated fatty acids as endogenous metabolites, bisphenol A and PFAS as endocrine disruptors, fatty acid binding protein 4, and soluble leptin receptor as circulating proteins, and gut microbiome features as predictors or modulators of metabolic disease.[1](https://hsph.harvard.edu/profile/qi-sun/)
## Cohorts and funding
His research is primarily based on large-scale cohort studies, chiefly the Nurses' Health Studies and the Health Professionals Follow-up Study, and he leads NIH-funded projects on food biomarker discovery and validation and on relationships between obesogens and weight change.[5](https://hub.nutritionsociety.org/content/plant-based-diets-quality/) His NIH grant R01DK120870, "Food-Based Biomarkers, Diet Quality, and Cardiometabolic Health," awarded $518,700 and ran from April 15, 2019 to March 31, 2025.[7](https://explore.openalex.org/awards/g5962171751)
## Representative work
- **"Smoking Cessation, Weight Change, Type 2 Diabetes, and Mortality"**, *New England Journal of Medicine* (2018), [doi:10.1056/nejmoa1803626](https://doi.org/10.1056/nejmoa1803626).
## Honors
The [American Heart Association](https://www.edgepedia.org/american-heart-association) awarded Sun the Trudy Bush Fellowship for Cardiovascular Research in Women's Health in 2008 and the Mark Bieber Award in 2013.[1](https://hsph.harvard.edu/profile/qi-sun/) His study findings have contributed to the US dietary guidelines for chronic disease prevention.[1](https://hsph.harvard.edu/profile/qi-sun/)
## References
1. Qi Sun, Harvard T.H. Chan School of Public Health profile. https://hsph.harvard.edu/profile/qi-sun/
2. Qi Sun, Harvard Catalyst Profiles. https://connects.catalyst.harvard.edu/Profiles/profile/1237717
3. Qi Sun, Synapse author record. https://synapsesocial.com/authors/69dc1f637e7b04fa41f6ecdf
4. Smoking Cessation, Weight Change, Type 2 Diabetes, and Mortality. *New England Journal of Medicine*, 2018. https://www.nejm.org/doi/full/10.1056/NEJMoa1803626
5. Plant-based diets, quality makes a difference, Nutrition Science Hub. https://hub.nutritionsociety.org/content/plant-based-diets-quality/
6. Meet Our Members: Qi Sun, MD, ScD, Harvard NIEHS Center. https://hsph.harvard.edu/environmental-health-niehs/news/meet-our-members-qi-sun-md-scd/
7. NIH award 5R01DK120870-05, OpenAlex award record. https://explore.openalex.org/awards/g5962171751
8. Qi Sun, MD, ScD, Channing Division of Network Medicine, Brigham and Women's Hospital. https://cdnm.bwh.harvard.edu/qi-sun-md-scd/
9. Five Questions with Qi Sun, Harvard Catalyst. https://catalyst.harvard.edu/news/article/five-questions-with-qi-sun/
10. Smoking, weight gain and type 2 diabetes, ABC Health Report. https://www.abc.net.au/listen/programs/healthreport/smoking-weight-gain-and-type-2-diabetes/10194240
11. Smoking cessation and weight change in people with type 2 diabetes. *The Lancet Diabetes & Endocrinology*, 2020. https://pubmed.ncbi.nlm.nih.gov/31924561/
12. Smoking cessation, weight gain and risk of cardiovascular disease. *Heart*, 2022. https://heart.bmj.com/content/108/5/375
13. White rice consumption and risk of type 2 diabetes: meta-analysis and systematic review. *BMJ*, 2012. https://www.bmj.com/content/344/bmj.e1454
14. Low-Carbohydrate Diet Macronutrient Quality and Weight Change. *JAMA Network Open*, 2023. https://pmc.ncbi.nlm.nih.gov/articles/PMC12635889/
15. Low-Carbohydrate Diets of Varying Macronutrient Quality and Risk of Type 2 Diabetes. *Diabetes Care*, December 2025. https://www.ovid.com/journals/dcar/pdf/10.2337/dc25-1401~low-carbohydrate-diets-of-varying-macronutrient-quality-and
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*Topic: Encyclopedia › Life and health › Life and health scientists › Medical and health researchers › Researchers in cardiovascular, metabolic, and endocrine research › Diabetes and endocrinology › Clinical diabetes and metabolism › Diabetes epidemiology and prevention*
*Initially written Sep 21, 2026 · Reviewed: Sep 25, 2026; Sep 30, 2026 · Edited: Sep 25, 2026 · Last review: Sep 30, 2026*
*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*
License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license