Dear Sirs

I read with great interest the report from Howell, Anderson, Allegria et al about the correlation of age, body mass index, and diastolic pressures. ^{Reference Howell, Anderson and Alegria1}

The exact prevalence and body habitus of CHD in the general population presupposes the existence of sufficient registries. In 2000, the incidence of CHD in adults was 4.09/1000 and 9% were severe. In addition, the average age of patients increased from 11 years in 1985 to 17 years in 2000. ^{Reference Marelli, Mackie and Ionesu-Ittu2} Lower body weight was observed in symptomatic patients with greater severity of heart disease. ^{Reference Brida, Dimopoulos and Kempny3,Reference Zaqout, Vandekerckhove and Michels4} Men with severe CHD appear to have higher rates of low body mass index. ^{Reference Sandberg, Rinnström and Dellborg5} Overweight and obese rates, however, increase with age. ^{Reference Malavazos, Capitanio and Chessa6} Younger patients with Fontan’s circulation had a lower body mass index than the general population, and this trend was reversed in those over 20 years of age. ^{Reference Freud, Webster and Costello7}

We conducted a retrospective study in our cardiac catheterisation laboratory during the years 2011–2019. The material consisted of 378 children from 2 to 19 years old who underwent heart catheterisation for acyanotic, cyanotic CHD, or other causes. Their anthropometric data were collected, and the body mass index was calculated.

The BMI centile was then calculated according to the Centers for Diseases Control definition. They were classified as overweight (85–95th centile), obese (> 95th centile), normal weight (5th–85 centile), and underweight (<5th centile).

18.7% of children were underweight, 54.76% were normal weight, 11.64% were overweight, and 14.81% were obese. Overall, 26.45% of the children were overweight. Boys were more likely to have increased body weight than girls, but the difference was not statistically significant. The percentage of increased weight was similar in children with acyanotic CHD as well as heart disease from other causes. However, children with cyanotic heart disease were more likely to be underweight 27.7% compared to 16.6% with acyanotic heart disease and 13.3% of children with other heart disease. Accordingly, children with cyanotic heart diseases were less likely to have increased body weight 15.7% than children who had cyanotic heart diseases 29.8% or other forms of heart disease 26.7% (Table 1).

Table 1. Anthropometric data

On the contrary, children with cyanotic heart disease were more likely to be younger and have a higher percentage of underweight. The difference of body weight between the types of catheterisation was small but statistically significant. Children of preschool age were thinner, while adolescents were the heaviest. The difference was statistically significant.

As the incidence of obesity in adults with CHD appears similar to that of the general population, it is important to clarify exactly when obesity begins. For example, it is important to investigate whether the foundations begin with poor dietary practices or unnecessary exercise restriction in childhood, or if they occur several years later, after the interventions are over.