The EPIC-Norfolk Study- Diabetes
- Physical Activity
- Diet
- Cancer
- Mental health
- Eye health
- Bone and skeletal muscle health
- Cognition
- Cardiovascular disease
- Lifestyle
- Research Impact
Diabetes
Research based on the EPIC-Norfolk cohort showed that glycated haemoglobin (HbA1c), a blood marker for chronic glycaemia, could be used to identify individuals in a healthy population at high risk of developing diabetes. The blood levels of HbA1c were shown to predict mortality in men across the whole range of concentrations, even below the threshold for diagnosis of diabetes.
The cohort has been used extensively to study risk factors for diabetes including reduced physical activity, weight and family history of diabetes. Risk of developing diabetes was also associated with lower blood levels of vitamin D, having an energy dense diet and consumption of soft drinks and sweetened-milk beverages. Higher fish consumption was shown to be protective of diabetes.
Physical activity
Physical activity has been widely studied in the EPIC-Norfolk cohort. The data collected from the physical activity questionnaires was used to develop a simple pragmatic index of physical activity, which combines both work and leisure time physical activity. It was found that compared to being inactive even those who were moderately inactive had about 20% lower risk of death and cardiovascular disease.
Moderate exercise in middle and older age has been found to cut time spent in hospital, with a significantly lower (25-27%) risk of long or frequent hospital admissions. In addition, regardless of past activity levels or existing health conditions, keeping active or becoming more active in middle and older age has been linked a lower risk of death and a reduction in cardiovascular disease. Dog walking is one form of exercise that has been shown to increase physical activity in the elderly, while a lack of exercise was found to be responsible for twice as many deaths as obesity.
Diet
Associations with diet scores
The data available on nutrients and foods from both food frequency questionnaires (FFQs) and 7-day diet diaries (7dDDs) have been used to investigate a number of hypotheses relating to the consumption of a Mediterranean diet. Greater adherence to the Mediterranean diet was found to be associated with lower CVD incidence and mortality in the EPIC-Norfolk population, with better cognitive function and lower risk of poor cognition in older adults, and with reduced fractures and better muscle health. Additionally, FFQ data were used to show that greater accordance to the Dietary Approaches to Stop Hypertension (DASH) diet was associated with lower diet-related greenhouse gas production but higher dietary costs.
7dDD- role of disaggregated food intake data
Disaggregated food intake data from 7dDDs has been used to show that greater low-fat fermented dairy product intake, largely driven by yoghurt intake, was associated with a decreased risk of type 2 diabetes development. The consumption of soft drinks, sweetened-milk beverages and energy from total sweet beverages was also found to be associated with higher type 2 diabetes risk, independently of adiposity, with the consumption of water or unsweetened tea/coffee appearing to be suitable alternatives to sugar-sweetened beverages (SSB) for diabetes prevention.
Dietary data from the 7dDD has been used to investigate the association between percentage of total daily energy intake consumed at breakfast and weight change in EPIC-Norfolk. Although all participants gained weight during the course of the study, those who consumed 22 to 50% of their energy at breakfast had the lowest BMI compared to people who consumed only 0 to 10% of their energy at breakfast.
Supplements
Vitamin and mineral supplements are an important source of micronutrient intake, which need to be taken into account when examining the relationship between intake of particular nutrients and health outcomes. A database was created to estimate the total nutrient intake of EPIC-Norfolk participants at the first health check. This database has enabled the total nutrient intake of vitamin C to be investigated in relation to measures of skeletal muscle mass and associations between omega-3 intake and coronary heart disease. A number of other studies, for example, looking at vitamin D, magnesium or magnesium and potassium have used this data to classify participants as supplement consumers in their analyses.
Cancer
The international EPIC study, of which EPIC-Norfolk is part, was set up to study the relationship between diet and cancer . A paper from 2010 summarises the contribution of this study to clarify the association between different dietary factors and cancer risk for six common cancer sites. For example, the EPIC study has contributed to a study showing that the risk of developing colorectal cancer is increased by a high consumption of alcohol and red and processed meat, while fibre and fish were shown to reduce the risk. Similarly, breast cancer risk is associated with obesity and a high consumption of saturated fat and alcohol.
Mental health
Psychosocial information collected in the Health and Life Experiences Questionnaire has been used to study the link between mental health and physical health. Participants reporting adverse experiences in childhood were found to have shorter telomere lengths, a molecular marker of ageing. In this cohort, a strong sense of coherence has been associated with a 30% reduction in all-cause mortality, while limited mastery was associated with a high risk of cardiovascular disease mortality. Studies of major depressive disorder found it to be linked to an increased risk of death from ischemic heart disease and the presence of either anxiety or depression was shown to have a detrimental effect on physical functioning, equivalent with being 12 years older or having a chronic condition. Generalised anxiety disorder was associated with an increased risk of death from cancer in men but not in women, while women living in a deprived area were more likely to have generalised anxiety disorder than those living in richer areas.
Eye health
Glaucoma is the leading cause of irreversible blindness in the world. The EPIC-Norfolk eye study examined the prevalence and characteristics of glaucoma and the distribution of intraocular pressure (IOP), the findings of which contribute to the planning of ophthalmic services in the UK. Studies of self-reported vision and falls also contribute an understanding of how to identify those at risk of vision-related falls.
High ocular perfusion pressure (OPP) is a risk factor for glaucoma. Data from 5,650 EPIC-Norfolk participants found that a high level of physical activity at baseline is associated with lower OPP 10 years later.
Studies of area-deprivation in association with low vision and age related macular degeneration (AMD) found both conditions to be more prevalent in deprived areas. These findings could help influence interventions to reduce health inequalities in the UK. Additionally, links between genetic variation, glaucoma and other eye conditions in EPIC-Norfolk participants contribute to an understanding of the mechanisms behind the conditions.
Bone and skeletal muscle health
Research on bone health has been enabled by measurements of bone density at the second health check through quantitative ultrasound of the heel, as well as linkage data on hospital admissions for fractures. The heel ultrasound measurement was shown to predict hip and total fracture risk in both men and women. Cross-sectionally in the EPIC Norfolk population, bone density was observed to decline 27% for women and 7.9% for men between the ages of 45 and 75. Bone density was positively associated with height, weight and BMI in both men and women, however the magnitude of association is much more pronounced in women. Time spent in high impact physical activity was strongly associated with bone density in both men and women, while in women, time spent watching TV was negatively associated.
Fat free mass measured at the second health check was used as a proxy for skeletal muscle mass. Adherence to a Mediterranean diet was shown to be protective for risk of fractures and skeletal muscle mass while a more acidic diet was associated with higher risk of fractures and lower skeletal muscle mass. Magnesium dietary intake was associated cross-sectionally with higher skeletal muscle mass.
Cognition
Cognitive function was measured as part of the 3HC of the EPIC-Norfolk study between 2004 and 2011. Some pioneering aspects of the memory tests were used. The detailed procedures used and comments on the advantages and disadvantages encountered when using these approaches have been published. It was discovered that full-scale scores of the Mini Mental State Examination can be generated from an abbreviated version. The future use of this abbreviated test could therefore be advantageous when testing under time constraints. Research into leisure-time inactivity and cognitive function in EPIC-Norfolk found that although physical activity during leisure time may be protective for cognition, work related physical activity is not.
Cardiovascular disease
Cardiovascular disease has been linked to many areas of diet and lifestyle in the EPIC-Norfolk study. Findings suggest that people who are able to adapt more rapidly to stressful circumstances in their lives had a lower risk of stroke and those sleeping for more than eight hours or less than six hours each night were found to be four times more likely to suffer a stroke. Eating a moderate amount of chocolate each day has been associated with a lower risk of heart disease and stroke in this population. Blood samples have been used to study molecular markers of cardiovascular risk including the role of HDL cholesterol and particle size and LDL particle number and size.
Lifestyle
Results from EPIC-Norfolk clearly presented that people who drink moderately, exercise, quit smoking and eat five servings of fruit and vegetables each day live on average 14 years longer than people who adopt none of these behaviours. Research into blood levels of vitamin C in EPIC-Norfolk participants showed that men and women with the highest levels of Vitamin C were 60% to 70% less likely to die from heart attacks or strokes than those with the lowest levels. Results revealed that even a small increase in fruit and vegetable consumption could have significant health gains and reduce the risk of an early death. An EPIC-Norfolk study found that each hour in front of the television per day multiplied the risk of death from heart disease by a factor of 7%, even after taking into account other well-known risk factors, such as lack of exercise, smoking, obesity and poor diet. Additionally, this study showed that the number of hours spent in front of the TV could be included in a future assessment of overall risk of heart disease. Longitudinal evidence from EPIC-Norfolk found that whilst retirement was associated with a decline in overall activity, physical activity did increase with retirement in respects to recreational and household pursuits. Furthermore, retirement was associated with a mean increase in TV viewing time, with the largest increase being among those who previously worked within the manual professions.
Sleep patterns have been linked to various health outcomes. Findings from EPIC-Norfolk participants showed that on average, the reported time in bed was 1.5h longer than sleep duration. Research into sleep characteristics found that sleep proportion may be a useful indicator of sleep patterns in the general population. Daytime napping was associated with an increased risk of all-cause mortality. Findings from EPIC-Norfolk found that this association was more pronounced for death from respiratory diseases and in individuals aged 65 years or younger.
Differentially methylated DNA sites in smokers in genes associated with smoking-related traits present in cancers, pulmonary function, inflammatory diseases, and heart disease, were not present in non-smokers. Researchers reported that these changes in methylation persisted many years after smoking cessation.
Research Impact
Diabetes – Research using EPIC-Norfolk data was important to establish the blood marker for glycated haemoglobin (HbA1c) as a screening and management tool, in particular the papers showing that HbA1c could be used to identify individuals at high risk of developing diabetes and that HbA1c is predictive of mortality. Two papers from 2006 are cited by NICE in their guidelines for the prevention of diabetes; one identifying risk factors such as age, weight, physical activity and family history and another showing that only 20% of participants met 3 out of 5 health goals among physical exercise, weight and consumption of fat and fibre.
Physical activity – The EPIC physical activity questionnaire was used to develop a 4-point physical activity index that can be used to summarize overall physical activity from participants of large epidemiological studies. Levels of physical activity measured by this index were linked to mortality and cardiovascular events. This index formed the basis of the General Practice Physical Activity Questionnaire which is recommend as screening tool for use in primary care.
Lifestyle – Research from EPIC-Norfolk showing that four simple health behaviours (not smoking, moderate drinking, regular exercise and fruit and vegetable intake of at least 5 servings per day) reduce mortality risk and increase self-reported quality of life is cited in the NICE guidelines for healthy ageing.