Inequalities in Health - Three English Towns

The inequalities in health by geography have been known for many years but the reasons are elusive. The phenomenon is particularly obvious for deaths from coronay heart disease (CHD), which has been the major cause of death in Europe and North America during the past 70 years (but not now). The reason for the variation has been and still is judged to be the result of faulty eating in those with the highest mortality, which in practice is those living in the north-west of England or the UK.

Three English towns have been studied in considerable detail.
Ipswich in south-east England has the lowest CHD mortality: 89 for men and 79 for women (Standardised mortality ratios (SMR), national average =100)
Stoke in the midlands has a CHD mortality SMR of 115 for men and 128 for women.
Wakefield in Yorkshire in the north of England has CHD mortality SMR of 115 for men and 137 for women.

We can see that mortality rates in Ipswich were below the national average, while those in Stoke and Wakefield were above the national average.

The study included data collection by house-to-house questionaires to establish dietary patterns. The expectation was more food, more fat, more sugar, more calories as we move north-west from Ipswich. In reality the opposite was determined. The residents of Wakefield in the north had the lowest nutrition intakes, most notably of fat, carbohydrate and total energy.

					Diet and coronary heart disease in 3 English towns Mean daily intakes of nutrients expressed as grams per day Death expressed as Standardised Mortality Ratios, ages 35-74 Number Energy Fat Carbohydrate Sugar Protein Fibre CHD (MJ) (g) (g) (g) (g) (g) deaths Men Ipswich 119 10.8 107.9 308.7 120.3 85.4 20.7 89 Stoke 128 11.6 107.9 315.1 117.0 94.5 20.2 115 Wakefield 110 10.1 96.5 271.2 106.0 84.1 17.9 117 Women Ipswich 129 7.1 73.0 192.2 76.5 64.3 15.1 79 Stoke 150 7.3 72.4 205.0 78.2 66.2 15.8 128 Wakefield 120 7.0 71.9 189.4 73.0 63.1 14.0 137

Reference:
Cade JE, Barker DJP, Margetts BM, Morris JA. Diet and inequalities in health in three English towns. Brit Med J 1988; 296: 1359-1362.

This is clearly a most interesting study, undertaken in considerable detail and well-produced. But its impact seems to be about zero. The results did not fit in with conventional wisdom, the diet-cholesterol-heart hypothesis. This finding which completely contradicts the diet hypothesis has been sidelined during the past 25 years and it is not in collective knowledge. There are many more examples of this.

So, what is the reason behind the mortality gradient in the UK from the south-east to the north? Could it be something to do with the location of the towns and the climate rather than collective human behaviour? Could it be the greater sunshine exposure of those living in Ipswich in the southeast that gives the advantage?

I would not advocate lack of sunshine as being the cause of death from CHD, but it increases suceptibility. More sun is a good thing.