Health behaviour and the COM-B model

What is health?

People with chronic health conditions can still manage to have a good quality of life thanks to advancements in medicine

Health is not a binary state → health on a sepectrum

WHO definition out of date and not fit for purpose due to ageing population and ability to manage chronic health conditions

Huber et al (2011) propose shifting the emphasis of health towards the ability to adapt and self manage in the face of social, physical and emotional challenges

Cause of death

In the 1900’s

Pneumonia / flu

TB

Diarrhoea

Heart disease

Intracranial lesions (vasc.)

Nephritis

Accidents

Cancer

Senility

Diphtheria

% of deaths from major causes in UK 2006 (Allender et al, 2008)

All cardiovasular diseases

• men - 35%

• women - 34%

All cancers

• men - 29%

• women - 26%

Respiratory disease

• men - 13%

• women - 14%

Accidents and injuries

• men - 5%

• women - 3%

Other causes

• men - 18%

• women - 23%

Just diseases of older age?

Summaries of the causes of death across the adult age group shows that it is not the case of being diseases of older age

• We see peaks in the 35 - 64 age groups

Younger people are dying of preventable causes

More apparent in cancer that is not just a disease of older age

Explaining these health outcomes

Over the past half century, it has been realised that behaviours such as smoking, dietary choice, alcohol consumption and regular physical activity play an important role in health outcomes

• Adler et al, 1999

Behavioural factors account for around 50% fo premature deaths from the 10 leading causes

• Gruman & Follick, 1998

The modern concept of health behaviour can be dated back to the Doll & Hill (1964) who studied British doctors in the 1950’s and found smoking was a major precursor of premature mortality

What are health behaviours?

Health behaviour - any activity undertaken for the purpose of preventing or detecting disease or for improving health / well being (Conner & Norman, 1996)

BUT health behaviours can have positive and negative health effects (Steptoe, Gardner & Wardle, 2010)

• Positive (protective) health behaviour can be defined as ‘activities that may help to prevent disease, detect disease and disability at an early stage, promote and enhance health, or protect from risk or injury’

• Negative (risky) health behaviour can be defined as ‘activities undertaken by people with a frequency of intensity that increases risk of disease or injury’

Broadest sense health behaviours - behaviours individuals engage in that affect their health

Measuring health behaviours

Behaviour is the currency of research into health behaviours

• ie. it is often the dependent variable

But behaviour is notoriously hard to measure

Typically measured using categorical or continuous measurements using self report questionnaires

• Eg. categorical - do you smoke? yes / no

• Eg. continuous - how many cigarettes do you smoke a day?

x - social desirability bias (under or over reporting)

x - subject to recall bias

Other measures include observation

• Eg. CCTV cameras to observe mask wearing in supermarkets

Or proxy measures

• Blood tests, step counters, pill counters

BUT proxy measures not always accurate

• Blood tests results can depend on metabolic rate

• Pill counters rely on pills actually being taken out of a bottle

• Step counters - errors in measurement, can be falsified

Number of health behaviours

Alameda county study (Belloc, 1973)

~ 7000 adults

Baseline postal questionnaire in 1965 followed by regular surveys of death and illness

7 baseline negative health behaviours predicted mortality

• Lack of exercise

• Snacking between meals

• Smoking

• Sleep (more than 8 hrs, less than 7)

• Skipping breakfast

• Regularly drinking more than 5 units of alcohol

• Over / underweight

7 features of a health lifestyle

Non-smoking

Moderate alcohol intake

7 - 8 hours per night sleep

Exercise regularly

Maintain a healthy body weight

Avoid high calorie snacks

Eat breakfast regularly

Belloc (1973) The relationship was so strong that they proposed that people aged over 75 years who carried out all 7 of the behaviours had health that was comparable to those aged 35-44 who did less than 3

Khaw et al (2008)

Analysed data from EPIC Norfolk longitudinal study of 20,000 men and women

Baseline no known CVD / cancer, aged 45 - 79

Followed up over 14 years

Survival was associated with four health behaviours

• not smoking

• being physically active

• drinking moderately

• eating 5 or more servings of fruit and veg a day

The fewer of these behaviours performed the greater risk of death

Preventable causes of death by health behaviour

Danaei et al (2009)

Investigation of deaths in the USA

Health behaviours can be lihnked to range of different causes of death

Eg. smoking atributable to CVD, cancer, diabetes and respiratory diseases

Health behaviours in the modern world

Several points emerge from the defintions of health behaviour and it’s study

1. The concept of health behaviours is fluid, and behaviours that are included can change as medical knowledge develops

2. Health behaviours are not uniformly important, but vary in their influence across time and across different populations

3. The strength of the evidence relatign behaviours with health outcomes is variable

• Case control, prospective, experimental, cross-sectional (but association DOES NOT equal causation)

• But consistent results with different samples and study designs, and a clear biological mechanism - stronger evidence

4. Behaviours may be done for non-health purposes, eg. limiting fat in the diet, going to the gym may be motivated by concern for appearance rather than health

Health psychologists need to view behaviour in a broad context and recognise that health motivations and cognitions are part of a wider set of infleunces on health behaviour

Important health behaviours in the modern world

Diet

• In 2018 only 28% of adults eating 5+ servings of fruit / veg a day (NHS, 2020)

Physical activity

• More than 80% of adolescents and 27% of adults do not meet WHO’s recomended levels of physical activity (WHO, 2022)

Smoking

• Rates declined over the last decade, but ~ 8 million adults in the UK smoke (ONS, 2021)

• Highest rate amoung 25 - 34 year old (ONS, 2021)

Sexual behaviour

• 47% of sexually active young people do not use a condom when sleeping with someone for the first time (YouGov Poll, 2017)

Alcohol

• 25 - 28% of adult drinkers in UK binge on alcohol on their heaviest drinking day (ONS, 2017)

Types of behaviour change

Different kinds of behaviour change

Initiate a new behaviour

• Eg. starting to recycle, wearing face masks

Stopping an existing behaviour

• Eg. stopping smoking, stop hugging friends / family

How a behaviour is performed

• Eg. changing frequency, intesnity, duration of a behaviour (exercising more, eating less)

Changing behaviour - what do we need to consider?

Our primary motivational concerns in life are the same for humans as they are for most animals (food, water, air, reproduction, etc)

Challenging these behaviours that are motivated by these systems can be difficult, for example

• Sexual behaviour - eg. condom use

• Energy seeking behaviour - eg. eating habits

• Energy conservation behaviour - eg. exercise levels

We need to first understand behaviour in order to change it, this requires adopting a biopsychological appeach to health

Understanding, and therefore attempting to change behaviour requires an appreciation of the evolutionary / biological, psychological and social contexts in which it takes place

Determinants of health behaviour - biopsychosocial approach

Biological determinants of health behaviour

Evidence from twin studies suggest there is a heritable component to smoking initiation, nicotine addiction as well as body weight and obesity (Plomin et al., 2000)

Some health behaviours have a physiological response (smoking, drinking, eating, exercising) releasing dopamine, endorphines which can reinforce the behaviour

The ability to carryout many health behavours is affected by personal

• Disabilities may impact ability to carry out physical activity

• Symptoms can act as cues to change or stop behaviour (eg. smoking, adherence to medications etc)

Social determinants of health behaviour

Health behaviours are strongly affected by peer group infleunces, family habits and social networks (Baranowski, 1997)

• Early socialisation (observational learning) → health habits eg. brushing your teeth, smoking

• Culturally valued or discouraged behaviour (eg. alcohol consumption in some religions)

• Peer pressure in adolescence = origin og many risk behaviours

Socioeconomic status (Pampel, Krueger, Denney, 2010)

• Financial barriers to health behaviours, lack of available resource, lower education

Legislative law (DeJong & Hingson, 1998)

• Eg. seat belt use, drink driving

Psychological determinants of health behaviour

Emotion (Ferrer & Mendes, 2018)

• Stress - smoking, drinking, overeating and exercise

• Fear - avoidance of health care → eg. dental, delay in reponse to symptoms, screening etc)

• Disgust - fear avoidance → blood test, cervical screening

Cognition (Armitage & Conner, 2000)

• Attitudes and beliefs

• Social cognition models (eg. Theory of Planned behaviour - Ajzen, 1991)

• Interventions based on theory of planned behaviour to improve health behaviour

COM-B model

Michie et al (2011)

COM-B - capability

The ability to enact behaviour

Made up of physical and psychological capability

Physical capability

• Physical skill / strength to perform the behaviour

• Eg. ride a bike, lift a 20kg weight

Psychological capability

• Capacity to engage in nencessary thoughts processes - knowledge, reasoning

• Eg. Knowledge of COVID-19 transmission and how to avoid it

COM-B - opportunity

Environment that enables behaviour

Made up of physcial and social opportunity

Physical opportunity

• Opportunity afforded by the environment

• Eg. close proximity to a gym, availability of cycle lane

Social opportunity

• Opportunity afforded by social / cultural norms

• Eg. people around you enjoy engaging in behaviour, reminders to do something, having support from people around you

• Eg. Being able to smoke in the house of another smoker vs work meeting

COM-B - motivation

Mechanisms that activate or inhibit behaviour

Made up of reflective and automatic motivation

Reflective motivation

• Evaluations (beliefs about what is good or bad), plan (intentions)

• Eg. drinking responsibly is a good thing to do

• Eg. planning to wake up early to go to the gym

Automatic motivation

• Emotional reactions, desires (wants and needs), impulses, inhibitions

• Anticipated pleasure at the prospect of eating piece of cake

Methods to collect data using COM-B

Questionnaires

• Specific questions about their capability / opportunity / motivation

• Reach larger groups of people

Interview / focus groups

• In depth qualitative data

• Ask open ended questiosn about capability / opportunity / motivation, barriers / facilitators of engaging in the desired behaviour

• Smaller samples

Observation

• Self report data questionnaires / interviews may be far away from the truth, observations useful tool to see what actual happens

How well can the COM-B explain behaviour?

Willmott et al (2021) - COM-B and physical activity

A cross sectional survey

Used validated measures to capture COM constructs and physical activity behaviour

Administered online to a sample of young adults aged 18 - 35 years

N = 582 (mean age = 22.8 years; 80.3% female)

The COM-B model explained 31% of variance in physical activity

• Capability and opportunity were found to be assoicated with behaviour through the mediating effect of motivation

• Increased capability + opportunity → increased motivation → increased physical activity

Designing interventions for behaviour change

Once you have considered behaviour in context (eg. collected data using the COM-B model) and understand what drives it you can begin to consider options for interventions

Michie et al (2011) developed a synthesis of 19 frameworks of behaviour change interventions to help with this - the behaviour change wheel (BCW)

• Comprehensive

• Coherent

• Linked to model of behaviour (COM-B)

Identified 9 intervention functions and 7 policy categories that could enable or support these interventions to occur

BCW - intervention functions

Michie et al (2011)

Intervention functions are activities to change behaviour

Behavioural diagnosis → aspects of COM-B that need addressing → intervention functions to change the behaviour

• Education - increasing people’s knowledge

• Persuasion - using communication to induce possitive or negative feelings

• Incentivisation - creating an expectation of reward

• Coercion - creating an expectation of cost or punishment

• Training - helping people to develop skills

• Enablement - giving people means to engage in behaviour or reduce barriers

• Modelling - providing an example for people to aspire to or emulate

• Environmental restructuring - changing the physical or social context

• Restrictions - using rules to reduce opportunity to engage in target behaviour

Matching intervention functions to COM-B

BCW - policy categories

Michie et al (2011)

Policies - decisions made by authorities interventions

Policy categories

• Environmental / social planning - designing and controlling the social environment (eg. creating cycle paths, parks)

• Communication & marketing - print, electronic media, broadcasting (eg. adverts about COVID vaccines or washing hands)

• Legislation - changing laws (eg. prohibiting sale or use of drugs

• Service provision - delivering a service (eg. cancer screening services)

• Regulation - establishing rules or principles of behaviour (eg. voluntary agreements on gambling / alcohol advertisement)

• Fiscal measures - using the tax system to increase cost (eg. sugar levy / alcohol tax

• Guidelines - creating documents that recommend or mandate a certain practice (eg. govt drinking guidelines or NHS physical activity guidelines)

Behaviour change techniques

Michie et al (2013)

Intervention functions are delivered by behaviour change techniques

Created a taxonomy of behaviour change techniques to help specify interventions and their active ingredients in more detail

Active ingredients within the intervention designed to change behaviour

• Observable

• Replicable

• Irreducible components of an intervention

Can be used alone or in communication

COM-B and the BCW in practice

Munir et al (2018)

Using BCW to develop an intervention to reduce sitting time at work

Focus group discussions with 39 NHS office workers based on COM-B model

Identified barriers / enablers related to

• Psychological capability (eg. knowledge of health risks of prolonged sitting

• Social opportunity (eg. social norms)

• Physical opportunity (eg. to have height adjustable desk)

• Automatic motivation (eg. need automatic reinforcement to change habit

• Reflective motivation (eg. beliefs about positive consequences of standing)

Used BCW intervention functions, policy categories and BCTs to identify appropriate strategies

Findings

Physical opportunities - don’t have height adjustable desks

• Intervention functions - environemntal restructuring, enablement

• BCTs - restructuring the physcial environment, adding objects (provide height adjustable workstations)

Social opportunities - social norms made it difficult to stand at a desk and work

• Intervention functions - modelling, enablement

• BCTs - demonstration of behaviour, social support

Psychological capability - limited knowledge of health risks of prolonged sitting

• Intervention functions - education

• BCTs - info about health consequences via seminars, instruction booklets

Reflective motivation - beliefs about positive consequences of standing were low

• Intervention functions - education, persuasion

• BCTs - info about health consequences via seminars, coaching session, feedback on outcomes of behaviour

Automatic motivation - staff need simple automatic reinforcement to change habit

• Intervention functions - environmental restructuring, incentivisation

• BCTs - prompts and cues (via the use of an app), self monitoring usign a diary of daily sitting and standing time