The Tromsø Family Intervention study: Effects of a family approach to reduce coronary risk factors in children of high-risk men

JC HEALTH 1994; 4: 181-187 The Troms0 Family Intervention study Effects of a family approach to reduce coronary risk factors in children of high-risk men SYNN0VE F0NNEB0 KNUTSEN • Key words: CHD, life-style intervention, diet, adolescents . revention of coronary heart disease (CHD), commencing with children and adolescents is intriguing because of the prospects of delaying or even preventing the atherosclerotic process before it has really started. On the other hand, motivating children and adolescents to change their life-style when there are no signs of disease, is difficult. Several studies have been done to assess the effect of life-style intervention in children and adolescents.1"10 Puska et al.1 reported that a 2 year intensive school-based intervention on health behaviour and CHD risk factors in 13-15 year old children resulted in a significantly lower increase in the proportion of both boy and girl smokers. For total cholesterol, no benefit was seen in boys, but in girls there was a significant decrease as compared to the reference population. In addition, for dietary habits, there was a significantly greater decrease in the intake of dairy fat both among boys and girls as compared to the reference population. No differences were seen in blood pressure. Botvin et al.2 studied the effect of a schoolbased intervention programme on being overweight and found a significant short-term effect (10 weeks) in the * S.F. Knutsen, Institute of Community Medicine, University of Tromsof Tromse, Norway and Department of Epidemiology and Biostatistics, School of Public Health, Loma Linda University, Loma Linda, California, USA Correspondence: Synnsve Fonneba Knutsen, MD, PhD, Department of Epidemiology and Biostatistics, School of Public Health, Loma Linda University, Nichol Hall, Rm 2010, Loma Linda, CA 92350, USA intervention group. Brownell et al.-3 also studied the effect of a 10 week school-based intervention programme on obesity and found significant decreases in the per cent overweight in the intervention group compared to the control group. Walter et al.4 studied the effect of a schoolbased programme aimed at lowering CHD risk factors. At 1 year, diastolic blood pressure was 1.1 mmHg lower in the intervention group and serum thiocyanate was 5.4 (i.mol/1 lower. These authors concluded that "Intervention programs in schools may, after sufficient duration, prove to be effective in lowering CHD risk". Walter et al.^ reported the 5 year results from the same study. A very small, but significantly larger rate of annual serum cholesterol decrease (1.7 mg/dl/year) was observed in the intervention schools as compared to the control schools in the middle- and upper-class areas. No differences were found between intervention and control schools in the lowerincome areas. Neither were there any significant differences in any of the other CHD risk factors. These authors concluded that "educational programs to modify coronary risk factors are feasible and may have a favourable (albeit small) effect on blood levels of cholesterol in children". Nader et al.6 studied the effects of a family-based CHD risk reduction intervention in Mexican and AngloAmerican families and found that after 1 year, diastolic blood pressure in the children was close to 3 mmHg lower than at baseline and the 'salt-score' was also significantly This study was done to assess the effect of intervention on coronary heart disease risk factors among children using a family approach. Men at increased risk of coronary heart disease (n=l,373) were randomly allocated to intervention and control groups together with their wives (n=l,143) and children (n=2,838). The intervention families received home visits by a physician and dietician, quarterly newsletters regarding diet, smoking and physical exercise and were invited to 'stop smoking' clinics and meetings on nutrition and exercise. At rescreening 6 years later, 29 of the control children exceeded pre-set risk factor limits compared with 15 in the intervention group (p<0.05). Children in the intervention group reported 'better' dietary habits than children in control families, especially for foods commonly eaten at home. At least 7 of the 9 'good' dietary habits were practised by 205 intervention children compared with 156 in the control group (p<0.01) and 88 versus 154 reported practising at least 3 of the 9 listed 'bad' dietary habits (p<0.001). No significant differences were found between the 12-24 year old children in the 2 groups in mean risk factor levels, the proportion of smokers or in the pattern of physical exercise. It was concluded that coronary heart disease risk reduction in children using the family approach is well received and results in dietary changes and a reduced number exceeding pre-set risk factor limits. The effect on mean risk factor levels, smoking and physical exercise was small. Targeting the intervention more directly to children could possibly improve the results. Also, life-style changes may require a longer follow-up before significant differences can be seen among teenagers. EUROPEAN JOURNAL OF PUBLIC HEALTH VOL. 4 1994 NO. 3 1,143 wives, 1,060 and 809 respectively attended the lower at 1 year compared to the baseline value. The 1986-1987 survey. This represents 87.2 and 93.1% of problem with this study is that it did not have a control those who had attended the 1979-1980 screening and group. Another study with only baseline and follow-up 8 were still living in the municipality. Of the 2,838 children measurements was the Heart Healthy Program which in these families, 1,749 were 12-24 years old in 1986 and reported substantial changes in eating behaviour and in were still living in the municipality in 1986. 1,498 of them knowledge about heart health and food preferences Of these, 1,103 (73.6%) attended the 1986-1987 survey. among children after having been given school-based 9 intervention. Thompson et al. reported significant differences in blood pressure after giving nutrition and phys- METHODS ical fitness intervention to school children. Based on The Family Intervention Study has been described in these studies, the effect of intervention clearly varies and detail elsewhere.13ll4'16Briefly, the 673 men in the intergenerally is quite small. It is likely and has also been vention group were informed in a letter that they had shown 10 that the eating habits of parents have an impact increased CHD risk and that their family was at increased on the nutrient intake of their pre-school children, thus risk due to a shared life-style. The whole family was offered furnishing indirect support for dietary intervention targethelp to reduce this risk. The intervention consisted of 2 ing families for the primary prevention of CHD. The fact home visits, first by a physician and 2-3 weeks later by a that life-styles tend to aggregate in families was the main dietician. The visits were done during the second year reason this study used (...truncated)