Hundreds of under-75s have died from stroke and heart disease in Calderdale in recent years, new figures show.
It comes after a British Heart Foundation report revealed deaths from cardiovascular diseases in the UK among under-75s have risen for the first time in more than 40 years.
Public Health England data shows 283 people under the age of 75 in the NHS Calderdale CCG area died from heart disease between 2015 and 2017, the latest period for which data is available.
It means a death rate of 51 in every 100,000 for the area, which is a five per cent increase on the death rate in 2011-13.
This reverses the trend of the previous six years - when the mortality rate dropped by 25 per cent - and bucks the national trend.
In addition, 88 people died from stroke in 2015-17 - a death rate of 16 in 100,000.
This is an increase of four per cent on the death rate in 2011-13, and also reverses the trend of the previous six years when the mortality rate dropped by 13 per cent.
The BHF also says historic reductions in mortality rates have “slowed to a near standstill".
It warns that millions of people are living with undiagnosed conditions including high blood pressure and diabetes that increase their risk of a fatal heart attack or stroke.
Professor Jamie Waterall, from PHE, said stopping cardiovascular disease remained a major challenge that required a united effort across society.
He said: “Supporting people to become more active, eat well, cut back on alcohol and quit smoking will help reduce the number of heart attacks and strokes, most of which are preventable.
“We also need to get better at detecting those at risk earlier and getting them the right support.”
He added: “If you’re over 40, getting your free NHS health check will help detect early warning signs of heart attack and stroke as well as other serious conditions.”
The BHF report, which used separate data, showed that 42,384 people died from cardiovascular diseases in the UK before the age of 75 in 2017 – around three per cent more than the 41,042 in 2014.
This comes after an almost uninterrupted fall in deaths since 1971.
It also shows how the pace of reducing deaths has slowed, dropping just nine per cent in 2012-17 compared to 25 per cent over the previous five-year period.
Simon Gillespie, chief executive of the BHF, said the UK had made "phenomenal progress" in reducing deaths from a heart attack or stroke.
He added: "But we're seeing more people die each year from heart and circulatory diseases in the UK before they reach their 75th, or even 65th, birthday. We are deeply concerned by this reversal.
"Heart and circulatory diseases remain a leading cause of death in the UK, with millions at risk because of conditions like high blood pressure and diabetes.
"We need to work in partnership with governments, the NHS and medical research community to increase research investment and accelerate innovative approaches to diagnose and support the millions of people at risk of a heart attack or stroke."