< Back to main page

Lifestyle and social inequalities in non-communicable diseases


Systems Epidemiology maintains a strong focus on the broad topic of lifestyle and social inequalities in cancer and non-communicable diseases. Lifestyle and other environmental factors have been estimated to cause a substantial proportion of non-communicable diseases, such as cancer, cardiovascular diseases, and diabetes. This suggests that many cases of non-communicable diseases would be preventable if changes in lifestyle were implemented. Smoking, alcohol, unhealthy diet, obesity and lack of physical activity are modifiable risk factors with sizeable prevalence, particularly among disadvantaged populations, and play important roles in the etiology of several non-communicable diseases. As this topic is vast and there is substantial coverage on this topic in Systems Epidemiology, we have grouped specific objectives under projects and/or areas of research. These are described below.

Photographer: Marius Fiskum

Ongoing activity 2000 - onwards:

The EPIC-Europe study is an extensive and ongoing investigation that examines the impact of diet, nutrition, lifestyle, and environmental factors on the occurrence of cancer and other chronic illnesses across various European populations. Initiated in the 1990s, this project is among the largest of its kind globally, involving over half a million participants from 10 countries in Western Europe and spanning over 30 years. As a prospective cohort study, EPIC-Europe collects baseline data from individuals prior to the onset of any disease, allowing for a comparative analysis over time to discern why certain individuals develop diseases while others do not. This approach offers critical insights into the development of cancers at different locations within the body and aids in the early detection strategies that enhance the prospects for successful treatment and improved survival rates. 

The findings from EPIC-Europe are instrumental in providing evidence-based guidance to governmental bodies and public health policymakers, informing strategies for cancer and chronic disease prevention. By disseminating research outcomes to the public, the study also plays a pivotal role in educating individuals about the benefits of healthy eating and lifestyle choices for disease prevention, thereby contributing to public health on a broad scale. 

Learn more about EPIC here. 

Guri Skeie EPIC-Norway Principle Investigator

 

This research area aims to explore the relationship between body fatness, changes in body fatness, and obesity over the lifecourse and the likelihood of developing cancer later in life.

Specific objectives:

Ongoing projects:

Completed projects:

Marisa Da Silva: PhD thesis
  • To estimate the fraction and preventable cases of all and major body fatness-related cancers attributable to weight gain. Link to publication.
  • To assess body mass index, weight change over 6 years and subsequent obesity-related cancer risk . Link to publication.
  • To identify factors associated with high weight gain and obesity duration in a representative sample of Norwegian women. Link to publication.
  • to examine the age at onset, duration, intensity, and trajectories of body fatness in adulthood in relation to risk of breast cancer subtypes. Link to publication.

Elin Evensen: PhD thesis
In the PhD-project “Overweight/obesity, body composition and bone mass in late adolescence: the relation with birth weight, childhood body mass index and growth. The Tromsø Study: Fit Futures, a longitudinal cohort study”, the aim was to study how early life factors such as birth weight, childhood body mass index (BMI, kg/m2) and growth are related to overweight/obesity, body composition and bone health in adolescence. Link to papers 1, 2, and 3. The first paper on this topic aimed to determine the presence and degree of tracking of overweight and obesity and development in BMI and BMI standard deviation scores from childhood to adolescence in the Fit Futures cohort from North Norway. Link to publication.

We have also validated the self-reported body mass index (BMI) in the Norwegian Women and Cancer study. Link to publication.

Cancer is currently the leading cause of death in Norway and the number of new cancer cases is projected to continue its rise. With improvements in early detection and treatment, the number of survivors is increasing. It has been estimated that 30-50% of cancer cases are preventable and a large portion has been attributed to lifestyle behaviours. In this topic, we aim to investigate a healthy lifestyle index, as a simple multifactor exposure measure representing a gradient of healthy lifestyle behaviours, and its association to cancer incidence and survival. 

Specific objectives:

Ongoing projects: 

  • Kristin Benjaminsen Borch as PI partner in SILICA - How do social inequality and sex impact the relationship between lifestyle and cancer (SILICA)? This project has been recently launched and aims to determine the impact of socioeconomic status (SEP) and sex on the relationship between healthy lifestyle factors and the risk of overall, colorectal, pancreatic, lung, and upper-aero-digestive tract (UADT) cancers. The study will use population attributable fractions (PAF) and absolute risks (AR) to quantify the impact of lifestyle factors on cancer risk by SEP and sex. The study will also examine the association between SEP and sex-specific metabolic signatures of healthy lifestyles on cancer risk.
  • EPIC project: Use of weighted outcome-specific versions of a Healthy Lifestyle Index in a multicountry European cohort
  • EPIC project: Aim to provide novel evidence of the impact of changing lifestyle habits on cancer risk in a multicountry European cohort 

Completed PhD project:

Sairah Lai Fa Chen. PhD thesis

  • Estimate the associations between Healthy Lifestyle Index (HLI) scores measured during adulthood and the incidences of common cancer types. Link to publication.
  • Estimate the associations between changes in Healthy Lifestyle Index scores between two timepoints during adulthood and the incidences of lifestyle-related cancer types. Link to publication.
  • Estimate the associations between prediagnostic Healthy Lifestyle Index score during adulthood and survival of breast, colorectal, and lung cancers. Paper submitted. 

Other completed projects:

  • EPIC publication: Investigate the impact of changes in lifestyle habits on colorectal cancer (CRC) risk in a multicountry European cohort. Link to publication.
  • EPIC publication: Investigate associations between adherence to healthy lifestyles and risks of Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL) in a large-scale European prospective cohort. Link to publication.
  • EPIC publication: Investigate the association between a healthy lifestyle index and pancreatic cancer risk in a large-scale European prospective cohort. Link to publication.
  • EPIC publication: Lifestyle changes in middle age and risk of cancer: evidence from the European Prospective Investigation into Cancer and Nutrition. Link to publication

This research area has provided insights needed to establish breast cancer as a smoking-related cancer, pointed to the possibility that smoking women may be more susceptible to colon, rectal and lung cancer than smoking men. The research commenced in 1990 and includes work from six (The Tromsø Study, The Tromsø Mammography and Breast Cancer study, The Norwegian Women and Cancer Study, The European Prospective Investigation into Cancer and Nutrition, The Smoking and Cancer cohort, The Multiethnic Cohort Study) cohorts as well as three large international collaborations. Research on smoking cessation based on a Randomized Controlled Trial was ongoing from 2010 to 2022. All results have been disseminated world-wide to the scientific community through talks at international conferences, press conferences, and scientific publications. The results have been disseminated to the public through interviews on international radio, TV channels, internet, printed and social media. The results are used in targeted preventive efforts locally as well as globally.

Specific objectives - ongoing

The overall aim is to investigate the association between smoking exposure and the risk of selected cancers and mortality and examine methods and predictors of smoking cessation.

Smoking and smoking cessation and effect on mortality and life-expectancy:

Smoking cessation, methods and prediction:

Smoking and breast cancer:

Completed PhD projects:

Eivind Bjerkaas PhD thesis

  • Smoking duration before first childbirth: an emerging risk factor for breast cancer? Results from 302,865 Norwegian women. Cancer Causes Control. Link to publication.
  • The association between lifetime smoking exposure and breast cancer mortality - results from a Norwegian cohort. Link to publication.
  • Social Inequalities and Smoking-Associated Breast Cancer — Results from a Prospective Cohort Study. Link to publication.

Yngve Bremnes. PhD Thesis

  • Different measures of smoking exposure and mammographic density in postmenopausal Norwegian women: a cross-sectional study. Link to publication.

Related published papers:

Smoking and colon and rectal cancer:

Completed PhD project:

Ranjan Parajuli. PhD thesis

  • Cigarette smoking and colorectal cancer mortality among 602,242 Norwegian males and females. Link to publication.
  • Smoking Increases rectal cancer risk to the same extent in women as in men: results from a Norwegian cohort study. Link to publication.
  • The Increased risk of colon cancer due to cigarette smoking may be greater in women than men. Link to publication.

Related published papers:

Smoking and lung cancer:

Completed PhD project:

Merethe Selnes Hansen PhD thesis

  • The fraction of lung cancer attributable to smoking in the Norwegian Women and Cancer (NOWAC) Study. Link to publication.
  • Smoking related lung cancer mortality by education and sex in Norway. Link to publication.
  • Sex Differences in Risk of Smoking-Associated Lung Cancer: Results From a Cohort of 600,000 Norwegians. Link to publication.

Related published papers:

  • EPIC publication: A risk model for lung cancer incidence. Link to publication.
  • EPIC publication: The role of smoking and diet in explaining educational inequalities in lung cancer incidence. Link to publication.

Smoking and epithelial ovarian cancer:

Smoking and cervical cancer:

Smoking and pancreatic cancer:

  • Inger Torhild Gram. Smoking and pancreatic cancer: a sex-specific analysis in the Multiethnic Cohort study. Link to publication.
  • EPIC publication: Cigarette smoking, environmental tobacco smoke exposure and pancreatic cancer risk in the European Prospective Investigation into Cancer and Nutrition. Link to publication.

Smoking and endometrial cancer:

  • EPIC publication: Cigarette Smoking and Endometrial Cancer Risk: Observational and Mendelian Randomization Analyses. Link to publication.
  • EPIC publication: Risk of endometrial cancer in relation to cigarette smoking: results from the EPIC study. Link to publication.

Smoking and oropharyngeal cancer:

  • EPIC publication: Combined effects of smoking and HPV16 in oropharyngeal cancer. Link to publication.

Smoking and cancer:

  • Smoking and Cancer- some contributions from the NOWAC and other cohort studies. Link to publication.
  • EPIC publication: Impact of cigarette smoking on cancer risk in the European prospective investigation into cancer and nutrition study. Link to publication.
  • EPIC publication: The effect of occasional smoking on smoking-related cancers: in the European Prospective Investigation into Cancer and Nutrition (EPIC). Link to publication.

This research field is covered by two ongoing project where the overall focus is to study the increased burden of living with cancer. The overall aim is to study the impact of self-rated health by modifiable lifestyle factors and socioeconomic conditions on survival in cancer patients using the Norwegian Women and Cancer study. Furthermore, we recently (October 2023) launched a project on the impact of experienced stressful life events and mental health on fatigue, lifestyle, medication, and use of health care services in cancer survivors using data from the Tromsø Study.

Specific objectives

Ongoing PhD projects:

Ida Løken Killie

  • To investigate the impact of socioeconomic factors and modifiable lifestyle factors on the association between SRH and mortality comparing pre-diagnostic SRH in cancer survivors with SRH in cancer-free women
  • To examine pre-diagnostic repeated SRH by socioeconomic conditions and modifiable lifestyle factors on recurrence and short- and long-term survival in cancer patients
  • To explore post-diagnostic SRH and type of treatment in prediction of survival in women with cancer

Rokshana Akter

  • To investigate the association between stressful life events, mental distress, and fatigue among cancer survivors
  • To investigate how stressful life events and mental distress are associated with modifiable lifestyle factors among cancer survivors
  • To investigate the association between stressful life events and mental distress with use of medication and health care services in cancer survivors

There is convincing epidemiological evidence suggesting that a healthy lifestyle, including physical activity, could substantially prevent the development of different cancers. In this research field, the overall aim was to examine the relationship between patterns of physical activity and the risk of different cancers and in survival among Norwegian women.

Specific objectives:

Completed PhD projects: 

Kristin Benjaminsen Borch. PhD thesis

  • Physical activity and the risk of postmenopausal breast cancer - the Norwegian Women and Cancer Study. Link to publication.
  • Physical activity and mortality among Norwegian women – the Norwegian Women and Cancer Study. Link to publication. 
  • Criterion validity of a 10-category scale for ranking physical activity in Norwegian women. Link to publication

Sunday Oluwafemi Oyeyemi. PhD thesis

  • Physical activity patterns and the risk of colorectal cancer in the Norwegian Women and Cancer study: a population-based prospective study. Link to publication.

Other completed projects:

Kristin Benjaminsen Borch:
  • Physical activity and risk of endometrial cancer in the Norwegian Women and Cancer (NOWAC) study. Link to publication.
  • Risk of lung cancer and physical activity by smoking status and body mass index, the Norwegian Women and Cancer Study. Link to publication.
  • Physical activity before and after breast cancer diagnosis and survival - the Norwegian women and cancer cohort study. Link to publication.
  • Competing mortality risks analysis of prediagnostic lifestyle and dietary factors in colorectal cancer survival: the Norwegian Women and Cancer Study. Link to publication.
  • Exploring geographical differences in the incidence of colorectal cancer in the Norwegian Women and Cancer Study: a population-based prospective study. Link to publication.
  • Physical activity and cutaneous melanoma risk: A Norwegian population-based cohort study. Link to publication.
  • No association between physical activity and primary melanoma thickness in a cohort of Norwegian women. Link to publication. 
  • Life-course trajectories of physical activity and melanoma risk in a large cohort of Norwegian women. Link to publication. 
  • Association of leisure-time physical activity with risk of 26 types of cancer in 1.44 million adults. Link to publication.

Other completed projects:

Active project (2017-2024)

This research area consists of two externally funded projects. An e-health project aiming to develop an ICT solution for health indicator data for non-communicable diseases resulted in a pilot study. The WARIFA project will develop a prototype of a combined early risk assessment tool that will provide individual citizens with personalised recommendations for the management of chronic conditions - such as cancer, cardiovascular diseases, diabetes and chronic respiratory diseases – which represent the leading causes of death for the citizens of the European Union. WARIFA will be available to individual citizens via a user-friendly interface on their smartphone.

Active project (2021-2024)

Musculoskeletal disorders (MSD) are the most common cause for sick leave, disability retirement and for attending primary care in Norway. Among MSDs, fibromyalgia is listed as the third most common condition in women after osteoarthritis, low back- and neck pain. Furthermore, there exists a socioeconomic gradient in MSDs, and ample evidence shows that experiences in early life can impact health and its determinants all through life. To better identify effective intervention strategies, it is necessary to improve the knowledge base of causes of socioeconomic inequalities in fibromyalgia, while accounting for the life-course dimension of health. This project aims to apply a life course approach to study self-reported fibromyalgia in a population-based prospective cohort of Norwegian adult women, exploring predicting factors and mediating pathways through the life course.

Publications: 
  • Lifestyle risk factors of self-reported fibromyalgia in the Norwegian Women and Cancer (NOWAC) study. Link to Publication.
Ongoing Objectives:
  • To assess the effect of adult lifestyle factors on the relationship between adult socioeconomic position (SEP) and self-reported fibromyalgia.
  • To assess the mediating effect of adult SEP and lifestyle factors on the relationship between childhood conditions (SEP and lifestyle factors) and self-reported fibromyalgia.