Evidence review · Her Way Forward
The Fifteen-Year Gap
Type 2 diabetes risk begins at 25 for South Asian, Black African and African Caribbean adults, and at 40 for the white population. The free NHS Health Check is offered from 40. For the group most at risk, systematic screening starts fifteen years late.
The finding
A structural gap, not a behavioural one
This is not a case of women failing to attend something they were offered. For the fifteen years in which their risk is already elevated, there is no systematic offer to attend. The national screening programme is age-gated on a threshold derived from a different population's risk curve.
That gap is precisely the space a trusted community organisation can occupy, and it is cheap to occupy. The intervention is a sentence a woman can say to her GP, and a reason to say it before she turns forty.
What the evidence says
Risk begins fifteen years earlier, and the screening offer does not move
High confidenceDiabetes UK states that people from Black African, African Caribbean and South Asian backgrounds are at risk of developing type 2 diabetes from the age of 25, against 40 for the white population. The NHS Health Check, which includes a diabetes risk assessment, is offered to adults aged 40 to 74.
Age in years
White population, risk period
South Asian, Black African, African Caribbean, risk period
NHS Health Check offered
The gap, elevated risk with no systematic offer
Sources: Diabetes UK, Ethnicity and type 2 diabetes; NHS Health Check eligibility, ages 40 to 74. Scale runs 25 to 74.
The BMI threshold is lower, and most women have never been told
High confidenceNICE public health guideline PH46 sets lower BMI action thresholds for South Asian, Chinese, Black African and African Caribbean adults. Standard thresholds were derived largely from white European data and do not reflect cardiometabolic risk accurately at equivalent BMI in these groups.
kg/m², NICE PH46
A supporting prospective UK study found British South Asians reached equivalent diabetes incidence at BMI 25, and African Caribbeans at BMI 27, compared with BMI 30 in Europeans.
Wandsworth has roughly 6,000 people who do not know they have it
High confidenceThe borough’s own health and care plan estimates around 6,000 residents with undiagnosed type 2 diabetes and 11,780 at high risk. It also records that only 45.4% of diagnosed patients complete all eight recommended care processes, so the gap does not close at diagnosis either.
Wandsworth’s Asian population is concentrated around Tooting, West Hill North, Roehampton and Furzedown, and almost 60% of Asian residents are under 40. That last figure is the one to sit with. The majority of the borough’s Asian population is inside the fifteen-year gap right now.
Physical activity is a genuine lever, independent of weight change
High confidenceType 2 diabetes is among the conditions where routine activity changes outcomes through a direct mechanism, by improving insulin sensitivity. This holds whether or not weight changes, which matters for a programme that does not want to make weight the subject.
Her Way Forward already runs the delivery mechanism. Fitwell classes on Mondays at £5, free walks through Battersea Park on Fridays, both women only, with reduced-cost places held for anyone who asks and no proof required. What this evidence adds is not a new activity. It is a reason to attach to the existing one that is specific, checkable, and aimed at women in their late twenties and thirties rather than only at those already unwell.
What we could not verify
A figure we removed
An earlier draft cited a median age at diagnosis of 55 for South Asian people against 67 for white Europeans, a twelve-year difference. Chasing the source, the SABRE study reports South Asian men diagnosed around five years younger than European, African and African Caribbean populations, who are diagnosed at roughly 66 to 67. Those two claims are not compatible, and we could not establish which population and measure the twelve-year figure described. It has been dropped rather than reconciled.
Two further limits worth stating. The Wandsworth undiagnosed and high-risk figures are modelled estimates against expected prevalence rather than counts of identified individuals. And nothing here is broken down by sex at borough level, so the specific position of women within these Wandsworth figures is inferred from national patterns rather than measured locally.
Why this matters for funding
Three properties make this unusually fundable for an organisation of Her Way Forward’s size.
- The gap is structural and documented. It is not a claim about unmet need that requires a survey to establish. It follows directly from two published eligibility rules that do not line up.
- The intervention is not a new service. It is information attached to sessions that already run, delivered by people the women already trust, in rooms they already come to.
- It is measurable. Ask women at Monday’s class whether they have had a diabetes risk check. Count how many go on to ask their GP for one. That is a real outcome, collected in the room, and it costs nothing.
One caution on that last point. A count of women who went on to ask their GP is a genuine output, and it is not evidence of prevented diabetes. Anyone reporting it should say which of the two they are claiming.
Sources
Published clinical guidance and official local data only. Where sources conflict, the conflict is reported above rather than resolved in favour of the stronger-sounding figure.
Full source list
- NICE public health guideline PH46 Type 2 diabetes: prevention in people at high risk. Lower BMI action thresholds of 23 and 27.5 kg/m² for South Asian, Chinese, Black African and African Caribbean adults.
- Diabetes UK, Ethnicity and type 2 diabetes Risk from age 25 for Black African, African Caribbean and South Asian backgrounds, against 40 for the white population.
- NHS Health Check Eligibility ages 40 to 74, including diabetes risk assessment.
- Wandsworth Health & Care Plan 2025–27 NHS South West London Integrated Care Board. Approximately 6,000 undiagnosed, 11,780 at high risk, 45.4% completing eight care processes.
- Ethnicity-specific BMI cutoffs for obesity based on type 2 diabetes risk in England Population-based cohort study, The Lancet Diabetes & Endocrinology, 2021.
- Ethnicity-specific obesity cut-points in the development of type 2 diabetes Prospective UK study across three ethnic groups. Equivalent incidence at BMI 25 in South Asians and 27 in African Caribbeans against 30 in Europeans.
- Southall and Brent Revisited (SABRE) Cohort study of nearly 5,000 middle-aged Londoners of European, South Asian, African and African Caribbean descent. Cited above only for the conflict it exposes.
- Census 2021 results for Wandsworth Insight and Analytics Team, London Borough of Wandsworth, April 2023. Ethnic distribution by ward and age profile.