Stage-matched nutrition guidance for patients at elevated risk for cardiovascular disease: A randomized intervention study in family practice

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Original Research

Stage-matched nutrition guidance for patients at elevated risk for cardiovascular disease: A randomized intervention study in family practice

J Fam Pract. 2002 September;51(9):751-758

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References

1. Pyorala K. CHD prevention in clinical practice Lancet 1996;348 Suppl 1:s26-s28.

2. Hiddink GJ, Hautvast JG, van-Woerkum CM, Fieren CJ, van-’t-Hof MA. Consumers’ expectations about nutrition guidance: the importance of primary care physicians Am J Clin Nutr 1997;65:1974S-1979S.

3. Gray DP. Dietary advice in British General Practice Eur J Clin Nutr 1999;53 Suppl 2:S3-S8.

4. De Bakker D., Abrahamse H., Van den Hoogen H., Braspenning J., Van Althuis T, Rutten R. Jaarrapport LINH 1998: contactfrequenties en verrichtingen in het landelijk informatie netwerk huisartsenzorg (LINH). Utrecht/Nijmegen, The Netherlands: NIVEL/WOK; 1999.

5. Van-Weel C. Nutritional guidance in general practice—a conceptual framework Eur J Clin Nutr 1999;53 Suppl 2:S108-S111.

6. Hiddink GJ, Hautvast JG, van-Woerkum CM, Fieren CJ, van-’t-Hof MA. Nutrition guidance by primary-care physicians: perceived barriers and low involvement. Eur J Clin Nutr 1995;49:842-851.

7. Horwath CC. Applying the transtheoretical model to eating behaviour change: challenges and opportunities Nutrition Research Reviews. 1999;12:281-317.

8. Prochaska JO, DiClemente CC. In search of how people change: applications to addictive behaviors American Psychologist 1992;47:1102-1114.

9. Cambell MK, DeVellis B, Strecher V, Ammerman A, DeVellis R, Sandler R. Improving dietary behaviour: the effectiveness of tailored messages in primary care settings Am J Public Health 1994;84:783-787.

10. Steptoe A, Doherty S, Rink E, Kerry S, Kendrick T, Hilton S. Behavioural counselling in general practice for the promotion of healthy behaviour among adults at increased risk of coronary heart disease: randomised trial. Br Med J 1999;319:943-947.

11. Van Weel C, Smith H, Beasley H. Family practice research networks. Experiences from 3 countries. J Fam Pract 2000;49:938-943.

12. Snedecor G, Cochran W. Statistical methods Iowa, USA: Iowa State University Press; 1991.

13. Rutten GEHM, Verhoeven S, Heine RJ, et al. NHG-Standaard Diabetes Mellitus Type 2 (eerste herziening) Huisarts Wet 1999;42:67-84.

14. Walma EP, Grundmeijer HGLM, Thomas S, Prins A, Van den Hoogen J, Van der laan JR. NHG-Standaard Hypertensie (eerste herziening) Huisarts Wet 1997;40:598-617.

15. Thomas S, Van der Weijden T, Van Drenth BB, Haverkort AFM, Hooi JD, Van der Laan JD. NHG-standaard Cholesterol Huisarts Wet 1999;42:406-417.

16. Allain CC, Poon LS, Chan CS, Richmond W, Fu PC. Enzymatic determination of total serum cholesterol Clin Chem 1974;20:470-475.

17. Burstein M, Scholnick HR, Morfin R. Rapid method for the isolation of lipoproteins from human serum by precipitation with polyan-ions. J Lipid Res 1970;11:583-595.

18. Fossati P, Prencipe L. Serum triglycerides determined colorimetrically with an enzyme that produces hydrogen peroxide Clin Chem 1982;28:2077-2080.

19. Friedewald WT, Levy RI, Fredrickson DS. Estimation of the concentration of low-density lipoprotein cholesterol in plasma without use of the preparative ultracentrifuge Clin Chem 1972;18:499-502.

20. Feunekes GI, van-Staveren WA, De-Vries JH, Burema J, Hautvast JG. Relative and biomarker-based validity of a food-frequency questionnaire estimating intake of fats and cholesterol Am J Clin Nutr 1993;58:489-496.

21. Voorlichtingsbureau voor de Voeding. Zo eet Nederland 1992: resultaten van de voedselconsumptiepeiling 1992 (results of the 1992 Dutch National Food Consumption Survey). The Hague, The Netherlands: Voorlichtingsbureau voor de Voeding (The Netherlands Nutrition Centre);1993.

22. Voorlichtingsbureau voor de Voeding. Nederlandse Voedings-middelentabel 1997 (Dutch nutrient data base). The Hague, The Netherlands: Voorlichtingsbureau voor de Voeding (The Netherlands Nutrition Centre); 1997.

23. Curry S, Kristal A, Bowen D. An application of the stage model of behavior change to dietary fat reduction Health Education Research 1992;1:97-105.

24. Sporny LA, Contento I. Stages of change in dietary fat reduction: social psychological correlates J Nutr Educ 1995;27:191-199.

25. Cupples ME, McKnight A. Randomised controlled trial of health promotion in general practice for patients at high cardiovascular risk Br Med J 1994;309:993-996.

26. Neil HA, Roe L, Godlee RJ, et al. Randomised trial of lipid lowering dietary advice in general practice: the effects on serum lipids, lipoproteins and antioxidants. Br Med J 1995;310:569-573.

27. Hellénius M-L, Krakau I, De Faire U. Favourable long-term effects from advice on diet and exercise given to healthy men with raised cardiovascular risk factors. Nutr Metab Cardiovasc Dis 1997;7:293-300.

28. Tang JL, Armitage JM, Lancaster T, Silagy CA, Fowler GH, Neil HAW. Systematic review of dietary intervention trials to lower blood total cholesterol in free-living subjects. Br Med J 1998;316:1213-1220.

29. Keys A, Anderson J, Grande F. Serum cholesterol response to changes in the diet IV: particularly saturated fatty acids in diet 2S-P. Metabolism 1965;14:776-787.

30. Dickman, A., Eijkhout, M. P., Loeve J.A. Werken en leren 1999-2000: feiten en cijfers over de arbeidsmarkt en het onderwijs in Nederland. Alphen a.d. Rijn, The Netherlands, Centraal Bureau voor de Statistiek (Statistics The Netherlands);2000.

31. Erkkila AT, Sarkkinen ES, Koukkunen H, et al. Concordance of diet with the recommended cholesterol lowering diet in patients with coronary heart disease. Eur J Clin Nutr 1998;52:279-285.

32. Lynch JW, Kaplan GA, Cohen RD, Tuomilehto J, Salonen JT. Do cardiovascular risk factors explain the relation between socioeconomic status, risk of all-cause mortality, cardiovascular mortality and acute myocardial infarction? Am J Epidemiol 1996;144:934-942.

TABLE 1
Baseline characteristics of patients in the intervention and control groups

	Intervention n=71	Control n=72	P¹
Sex (%)
Male	24	29	0.48
Female	76	71
Age (years)	58.5±7.1	58.2±6.9	0.83
Disorder (%)
Hypertension	94	89	0.34
Diabetes mellitus II	6	7
Hypertension & diabetes mellitus II	0	4
Marital status (%)
Single	6	3	0.83
Married/cohabiting	82	86
Divorced	1	1
Widowed	11	10
Education (%)²
Low	68	68	0.91
Intermediate	20	18
High	13	15
Family history of heart disease (%)³	27	22	0.81
Smoking (%)⁴
Not smoking	79	78	0.70
Light smoker	13	10
Heavy smoker	9	13
Exercise, more than 20 minutes
No exercise	20	13	0.42
Less than 3 times a week	37	30
3 times a week	18	26
More than 3 times a week	25	31
¹Two-sided P values for differences in baseline characteristics between intervention and control groups.
²Low: primary school, lower level of secondary school, lower vocational training. Intermediate: higher level of secondary school, intermediate vocational training. High: higher vocational training, university.
³First-degree relatives younger than 60 years.
⁴Light smoker: 0-10 cigarettes a day, or smoking pipe or cigars. Heavy smoker: > 10 cigarettes a day.

FIGURE 1
Selection and flow of participants

Measurements

Specially trained practice assistants measured anthropometry data, and presented patients with a self-administered questionnaire on demographics, medical history, food frequency, and a stages-of-change algorithm at baseline, 6 months, and 12 months. Blood samples were taken at baseline and at 12 months.

Physical assessment. Anthropometry consisted of body weight to the nearest 0.5 kg, height, and waist and hip circumferences to the nearest 0.5 cm. Patients wore no shoes and only light clothing when weighed. Fasting blood samples were taken twice per measurement period at a 1-week interval, with the patient in the sitting position. The samples were stored at -80°C. Lipids were analyzed enzymatically for total cholesterol,¹⁶ HDL cholesterol,¹⁷ LDL cholesterol, and triglycerides¹⁸ with the Cobas Intergra 700 (Roche Diagnostics, Switzerland), at the laboratory of the Canisius Wilhelmina Hospital (Nijmegen, The Netherlands). The coefficient of variation within runs was 2.3% for total cholesterol, 1.6% for HDL cholesterol, and 1.8% for triglycerides. The LDL cholesterol level was calculated using the equation of Friedewald et al.¹⁹

Questionnaires. The questionnaire asked for demographic data, family history of heart disease, smoking status, physical activity, drug use, and diet history at baseline. At follow-up we checked for changes in smoking status, physical activity, and drug use. Patients in the control group were asked if they had visited a dietician during the study period. The intake of energy, total fat, fatty acids, and cholesterol during the preceding 4 weeks was assessed by asking patients to fill out a food frequency questionnaire that included 104 food items. The questionnaire was validated²⁰ and recently revised according to the Dutch National Food Survey 1992.²¹ Dieticians carried out nutrient calculations with a computerized version of the Dutch food composition tables²² phoned patients in cases of inconsistency.

Stages of change for reduction of fat intake were assessed with a 4-item algorithm based on measures used in previous studies^23,23 in combination with the results of the food frequency questionnaire. According to the algorithm, participants were judged to be in precontemplation if they did not consider their diet to be low in fat, they were not in the process of cutting down on fat, and they had no intention of reducing their fat consumption. Participants were considered to be in the contemplation phase if they intended to decrease their fat intake within 6 months but not within 30 days, and to be in preparation when they intended to decrease their fat intake within 30 days. Participants who reported they were currently trying to eat less fat were classified as in action, and participants who reported they had been eating less fat for at least 6 months were classified in maintenance. If participants in maintenance consumed 37% total fat or 12% saturated fat expressed as percent of energy intake, they were reclassified in precontemplation.

After completing the study, all patients filled in an evaluation questionnaire. Patients in the control group were also asked about which nutrition information they had received during the last year.

Intervention

The intervention consisted of nutrition counseling based on stages of change, directed by the FP with selective referral to a dietician. FPs were supported by a protocol that included Prochaska’s⁸ processes of change. Preparation and action stages were considered 1 stage (action stage) in this study, given the required nutrition education. (Figure 2) summarizes the intervention procedure: 1) counseling aimed at raising consciousness about dietary behavior in the precontemplation stage, 2) motivation to change dietary behavior in the contemplation stage, and 3) if a patient decided to change (action stage), information about practical aspects of dietary change and discussion of referral to a dietician. The intervention was conducted by the patient’s own FP. All patients were referred to the same dietician. Protocols for the FPs and the dietician had been developed and tested prior to the study and were discussed by FPs and the dietician in pre-study group sessions.