Lifestyle and Major Diseases

Did you know that lifestyle factors have an impact on major diseases? Studies show that Lifestyle is the most powerful tool in preventing chronic diseases.
Lifestyle factors, primarily not smoking, maintaining a healthy body weight (BMI 18.5–25), regular physical activity (at least 150 minutes of moderate exercise per week), healthy diet (e.g., Mediterranean-style, rich in fruits, vegetables, whole grains, and low in processed foods/red meat), and moderate or no alcohol consumption, have profound effects on preventing chronic diseases.
Below is an expanded breakdown of the claims, supported by major epidemiological studies and meta-analyses.
The five pillars of Lifestyle Medicine I learned in the Lifestyle and Wellness Coaching Course from Harvard Medical School Executive Program can be remembered using the
NESSS mnemonic device:

1. N – Nutrition
2. E – Exercise
3. S – Sleep
4. S – Stress
5. S – Social Relationships/Spirituality
6. S – Substance Abuse- Avoidance of Risky Substances
   To these, I would add one more:
7. P – Purpose & Meaning

My model of Lifestyle medicine is NESSSSSP
Between N for Nutrition, to which I would add Nature and Nurture, E for Exercise, to which we can add Energy or Vitality, and P that stands for our life’s Purpose and Meaning, there are four S letters.
We must remember that Stress influences all the other six factors.
Chronic stress is a significant factor that affects:
– Nutrition through poor digestion, gut and microbiome dysfunction,
– Sleep through insomnia and restlessness
– Social Relationships through irritability and withdrawal
– Substance Abuse – chronic stress can lead to increased alcohol, medication, or even risky substance intake that can cause addiction.
– Gets us burned out, exhausted, and sick to the point that we have no more energy to think about our life purpose and meaning.
It is a vicious circle that should never occur if we are aware of all this and pay attention to destressing, meditating, taking breaks, and maintaining mental and physical hygiene.
We must remember that it is okay to do nothing – to meditate, to take breaks so we can relax our nervous system and transition from the Sympathetic ‘Fight, Flight, or Freeze’ state into the parasympathetic ‘Rest and Digest’ state, where we should be, ideally.
Spirituality is an excellent remedy for stress, as prayer and positive thinking are effective de-stressors.

1. Lifestyle Factors Can Reduce the Risk of Cardiovascular Disease by Over 80%

• Evidence: The INTERHEART study (Lancet, 2004) identified nine modifiable risk factors (smoking, lipids, hypertension, diabetes, obesity, diet, physical activity, alcohol, psychosocial factors) that account for >90% of the population-attributable risk for myocardial infarction globally. www.pubmed.ncbi.nlm.nih.gov
• Nurses’ Health Study & Health Professionals Follow-up Study (NEJM, 2000; updated analyses): Individuals adhering to five low-risk lifestyle factors (never smoking, BMI <25, ≥30 min/day moderate-to-vigorous activity, moderate alcohol, high diet quality score) had an 82% lower risk of coronary events compared to those with zero factors. nejm.org +1Mechanism: These factors reduce atherosclerosis, hypertension, dyslipidemia, and inflammation—core drivers of heart disease.

2. Lifestyle Factors Can Reduce the Risk of Diabetes by Over 90%

• Diabetes Prevention Program (DPP) (NEJM, 2002): An intensive lifestyle intervention (resulting in 7% weight loss and 150 minutes of weekly activity) reduced the incidence of diabetes by 58% in high-risk adults—more effective than metformin (31%).
  pmc.ncbi.nlm.nih.gov +1
• Finnish Diabetes Prevention Study (NEJM, 2001; follow-ups): 58% risk reduction with similar lifestyle changes.
  pubmed.ncbi.nlm.nih.gov +1
• Combined analysis (Diabetes Care, 2023; prior meta-analyses): Adherence to four or five healthy behaviors (non-smoking, healthy weight, physical activity, healthy diet, low alcohol) was associated with a 93% lower risk of type 2 diabetes over 10–20 years. diabetesjournals.orgMechanism: Weight control and exercise improve insulin sensitivity; diet reduces glycemic load and visceral fat.

3. Lifestyle Factors Are Attributed to 40% of Dementia Cases

• Lancet Commission on Dementia (2020): Identified 12 modifiable risk factors (less education, hypertension, hearing impairment, smoking, obesity, depression, physical inactivity, diabetes, social isolation, excessive alcohol, air pollution, traumatic brain injury) that account for ~40% of dementia cases worldwide.
  alzint.org +2
• Key contributors: Midlife hypertension, obesity, and physical inactivity each contribute ~5–7%; smoking ~5%; diabetes ~3%.
• FINGER Trial (Lancet, 2015): A multidomain intervention (including diet, exercise, cognitive training, and vascular risk management) improved cognitive function in at-risk elderly individuals.
  thelancet.com +1

  Implication: ~60% of dementia risk is non-modifiable (genetics, age), but 40% is potentially preventable through lifestyle.

4. Lifestyle Factors Are Attributed to 42% of Cancer Cases

• American Cancer Society & WHO estimates (CA Cancer J Clin, 2022): 42% of cancer cases and 45% of cancer deaths in the U.S. are attributable to modifiable risk factors.
  pubmed.ncbi.nlm.nih.gov +1
• Breakdown:
  • Tobacco: ~19% of cancers
  • Obesity: ~7.8%
  • Alcohol: ~5.6%
  • Poor diet/low fiber: ~5.2%
  • Physical inactivity: ~2.9%
  • UV exposure, infections, etc.: remainder
• Global Burden of Disease Study (Lancet, 2022; 2019 data): Similar proportions internationally, with ~44% of cancer DALYs attributable to modifiable risks like tobacco, alcohol, and diet.
  thelancet.com +1
• Mechanism: Smoking causes DNA damage; obesity promotes inflammation and hormones (e.g., insulin, estrogen); alcohol is a carcinogen; exercise reduces colon/breast cancer via hormonal and immune pathways.

Summary Table

Key Takeaways:

Adopting these core healthy behaviors can prevent disease:
– Quit smoking
– Maintain a healthy weight
– Stay active and exercise moderately
– Nutrition – the Mediterranean Diet is highly recommended. Variety, fiber, and probiotic foods are key.
– Low alcohol consumption
– Stress management
– Social Connections – friends, hobbies, spirituality
– Vocation, Purpose, and Meaning – love what you do and do things for others. Give back!
Research shows that a healthy lifestyle is key to preventing the vast majority of heart disease and diabetes, and reducing dementia and cancer risk by 40–42%.
These are not theoretical—long-term cohort studies and RCTs confirm that lifestyle is the most powerful tool in preventing chronic diseases.

Sources

1. Yusuf S, et al. Effect of potentially modifiable risk factors associated with myocardial infarction in 52 countries (the INTERHEART study): case-control study. Lancet. 2004;364(9438):937-952. PubMed
2. Stampfer MJ, et al. Primary Prevention of Coronary Heart Disease in Women through Diet and Lifestyle. N Engl J Med. 2000;343(1):16-22. NEJM
3. Diabetes Prevention Program Research Group. Reduction in the Incidence of Type 2 Diabetes with Lifestyle Intervention or Metformin. N Engl J Med. 2002;346(6):393-403. NEJM
4. Tuomilehto J, et al. Prevention of type 2 diabetes mellitus by changes in lifestyle among subjects with impaired glucose tolerance. N Engl J Med. 2001;344(18):1343-1350. (Finnish DPS; referenced in follow-up analyses)
5. Aune D, et al. Combination of Multiple Low-Risk Lifestyle Behaviors and Incident Type 2 Diabetes: A Systematic Review and Dose-Response Meta-analysis of Prospective Cohort Studies. Diabetes Care. 2023;46(3):643-651. (Updates prior meta-analyses, including BMJ-related work)
6. Livingston G, et al. Dementia prevention, intervention, and care: 2020 report of the Lancet Commission. Lancet. 2020;396(10248):413-446. Lancet
7. Ngandu T, et al. A 2-year multidomain intervention of diet, exercise, cognitive training, and vascular risk monitoring versus control to prevent cognitive decline in at-risk elderly people (FINGER): a randomised controlled trial. Lancet. 2015;385(9984):2255-2263. Lancet
8. Siegel RL, et al. Cancer statistics, 2022. CA Cancer J Clin. 2022;72(1):7-33. PubMed
9. GBD 2019 Cancer Risk Factors Collaborators. The global burden of cancer attributable to risk factors, 2010-19: a systematic analysis for the Global Burden of Disease Study 2019. Lancet. 2022;400(10352):563-591. PubMed