C-Score is a health app that provides the public with a simple way of measuring their general health via their smartphones in 10 minutes.

Developed by Chelsea Football Club start up Chelsea Digital Ventures and digital healthcare experts HUMA, the app evaluates seven lifestyle factors, which have all been validated as key predictors of disease and mortality. These are:

1. Self-rated health - the app asks you how you feel about your overall health, since you know your body best
2. Resting heart rate - the app measures your heart rate simply by placing your finger over the smartphone’s camera
3. Sleep - the app contains a questionnaire that captures how many hours you’ve slept on average over the last week and the quality of that sleep
4. Smoking - the amount of tobacco cigarettes you smoke during an average week
5. Alcohol consumption - the type(s) and volume of alcohol you drink during an average week
6. Waist to height ratio - your smartphone’s camera is used to determine your waist circumference (you may need an extra pair of hands to help you). 
7. Reaction time - a simple test where you lift your finger once a shape changes colour.

Once users have completed each domain – which should take no more than 10 minutes - they are provided with a points-based measure, or ‘C-Score’ (a number between 0-100) which will reflect their general health. The higher your C-Score score, the better your general health is.

The score is compared against 500,000 people in the UK Biobank, a national health database made up of individuals aged between 40-69 years whose health data was collected between 2006-2010 and who are still sharing their data so their health can be tracked.

Users will be able to see how their health compares to the people in the UK Biobank, and what percentage of people in the UK Biobank gave similar or different answers to them or had data in the same or different range as them.

Whilst the C-Score domains aren’t all the factors that make you healthy or unhealthy, they are modifiable indicators that scientists and clinicians have taken from the medical literature as having the greatest impact on a person’s general health and as being all-cause mortality indicators.

They were selected in the following ways:

Medical literature review:

• A literature review of c. 500 publications was conducted by Huma’s clinical and scientific team to map out relevant domains for an all-cause mortality measure

Interviews with 24 key opinion leaders in three continents

• Refinement of relevant domains with 24 key opinion leaders from across the UK, US & China, including the likes of Dr Smisha Agarwai, Digitial Population Health at John Hopkins, Prof. Kamudi Joshipura, Cardio-metabolic Epidemiology at Harvard School of Public Health and Dr. You Cian Lin at China Medical University
• Confirmation of a final seven metrics with KOLs focussing on clinical and academic relevance, whilst being actionable and simple to measure by the general public

C-Score does not require invasive hospital tests, a visit to the GP, or expensive wearables, while the existing BMI model represents populations, not individuals.