JOURNAL OF ADOLESCENT HEALTH CARE 1:229-231, 1981

Long-Term Follow-up of Obesity in Adolescents

MARTIN FISHER, M.D. , ROSLYN NITKIN, M.S.R.D. , I. RONALD SHENKER, M.D. ,

AND MICHAEL NUSSBAUM, M.D.

Fifty adolescents, 12-17 years of age, were treated for obesity from 1967 to 1972. They were contacted in 1977 to obtain follow-up data. Each subject had been treated in a program of dietary counseling and behavior modi- fication. Mean weight on follow-up was 18.1 Ib (8.2 kg) lower than mean initial weight (P <0.05). The mean de- crease over desired weight was 29.5%. Twenty-tw0 pa- tients reported a weight loss of ~20 lb (P K0.001). (9.1 kg) and 15 patients reported a weight loss of 0-20 lb (9.1 kg). Thirty-eight precent of th e patients were no longer obese (~ 20% over ideal bodY weight) and an additional 22% were no longer overweight (10-20% over ideal body weight). These results suggest that a dietary and behavior modification program offered to adolescents may show beneficial results in young adulthood.

KEY WORDS: Adolescence Behavior modification Obesity

The treatment of obesity is difficult at any age. Al- though satisfactory short-term results can be achieved from a variety of treatment regimens, these results are seldom maintained during long-term fol- low-up (1-3). It has been suggested that behavior modification improves long-term outcome (4-6). We studied the long-term effects of a combined dietary and behavior modification program on a population of obese adolescents.

From the Department of Pediatrics, Division of Adolescent Medicine, Long Island Jewish-Hillside Medical Center, New Hyde Park, and Health Sciences Center of State University of New York at Stony Brook, Stony Brook

Direct reprint requests to: Martin Fisher, M.D., Long Island Jewish- Hillside Medical Center, Division of Adolescent Medicine, New Hyde Park, NY 11042.

Manuscript accepted November 27, i980.

M e t h o d s

Between 1967 and 1972, 150 adolescents from 12 to 17 years of age were evaluated and treated for obe- sity at the Long Island Jewish-Hillside Medical Cen- ter Adolescent Clinic. A telephone follow-up study of these patients was undertaken in 1977. Fifty sub- jects, one-third of the initial group, were available for follow-up; the whereabouts of the remaining subjects could not be determined. On follow-up, the study subjects were asked to supply a current weight and height, a retrospective self-assessment of their adolescent clinic experience, and information re- garding other attempts at weight loss. The mean time interval at follow-up was 7.7 years and the pa- tients were then between 18 and 27 years of age.

At the time of entry into the treatment program, each adolescent had a medical evaluation. The social worker and other consultants were utilized when indicated. All patients were seen by the nutritionist for individual dietary and supportive counseling. Group therapy was not employed. A dietary pro- gram of 1000-1400 cal/dav, with the use of an ex- change system, was instituted. Each patient was in- structed to maintain a daily food diary. Behavior modification techniques were introduced and exer- cise periods were encouraged (Table 1). Follow-up visits were scheduled on a weekly or biweekly basis. The group under study returned for 2 to 50 visits (mean 15.0).

All patients were initially >20% over desired weight for height, which we define as obese (7). Forty-five of the 50 follow-up subjects offered a def- inite response for current weight at follow-up, while five did not. Data regarding changes in weight and percent overweight were calculated only for the 45 definite responders. In order to be conservative in interpreting our data , we considered the five non-

© Society fo r Adolescent Medicine, 1981 229 Published by Elsevier North Holland, Inc., 52 Vanderbilt Ave., New York, NY 10017 iSSN 0197-0070/81/010229-03t$02.25

230 FISHER ET AL. JOURNAL OF ADOLESCENT HEALTH CARE Vol. 1, No. 3

definite responders still to be obese at follow-up. Data regarding individua ! response rates and weight classifications at follow-up were therefore calculated using all 50 subjects. Student's t -test or chi-square analysis was employed to test statistical significance.

Results The average age of the 45 respondents at initial visit was 14.2 years. There were 29 females and 16 males. Thirty-eight of the patients were white and seven were black. The range of socioeconomic status was consistent with that generally seen in the adolescent clinic: 15 lower income, 22 middle income, 8 upper income.

For the 45 respondents, the initial mean weight was 177.6 lb (80.7 kg). The reported mean weight at follow-up was 159.5 lb (72.5 kg). The mean dif- ference of 18.1 lb (8.2 kg) is significant at a level of P <0.051 For the group, the mean percent over- weight was 58.2% at the initial visit; at follow-up this had declined to 20.2%. The mean difference of 38% is significant at the P <0.001 level. This differ- ence takes into consideration both reported change in weight and reported or projected increase in height, a factor of critical importance in interpreting the follow-up data of growing adolescents.

The tendency to underestimate weight and ov- erestimate height on telephone follow-up has been established, necessitating a correction for percent overweight: corrected percent overweight=(1.14) x (reported percent overweight) + 5.9(8). Using this correction factor, the mean percent overweight

Table 1. Treatment Regimen Employed for Adolescent Obesity at Long Island Jewish-Hillside Medical Center Adolescent Clinic

1. Diet a. 1000-1400 cal b. Food exchange system c. Daily food diary

2. Behavior modification a. Eating only at dining room table b. Salad before entree c. 64 'oz. water daily d. Use of small plates e. Leave table at end of meal f. No shopping before meals

3. Exercise a. Incorporate into life-style b. Maintain daily record c. Extra exercise for extra food

at follow-up may increase to 28.7% from the re- ported 20.2%. Although this reduces the mean dif- ference between initial evaluation and follow-up from 38.0% to 29.5%, the difference is still significant at the P <0.00i level (Table 2).

The mean weight change during the initial treab ment period (i.e., while attending the nutrition counseling sessions) was 0.0 lb, with over 50% of the patients having gained weight during this pe- riod. There were no significant correlations (r) be- tween change in percent overweight on follow-up v. weight loss during treatment (r = -0.07), initial age (r = 0.13), years of follow-up (r = 0.14) or num- ber of visits (r = 0.17). There was a significant cor- relation between change in percent overweight and initial percent overweight (r = 0.56), suggesting that the most weight was lost by those who were most obese.

During initial treatment, females had a mean weight loss of 6.6 lb (3.0 kg), while males had a mean weight gain of 12.0 lb (5.5 kg). This is signif- icant at P <0.01 level. Mean weight loss from the time of initial visit to time of follow-up was also greater for females. Decrease in percent overweight during this period, however, was greater for males than for females (Table 2). There were no statis- tical differences noted by race in either the treatment or follow:up periods.

Individual responses of al! 50 subjects show that 22 patients reported a weight loss of > 20 lb from time of initial visit to the time of follow-up; 15 pa- tients reported a loss of 0-20 lb and 8 patients re- ported a weight gain during the period. Table 3, based on raw and corrected data, indicates that 22-~3(j% of the 50 study patients were no longer ov- erweight at follow-up and 16-24% were overweight but no longer obese. Surprisingly, only five patients indicated they had pursued other weight loss pro- grams during the follow-up period.

Discussion Available studies indicate that the attainment of a non-obese status can be expected in less than 20% of Untreated obese adolescents (9-11). Within the constraints of a telephone follow-up, results of this study show a non-obese young adult status for 38'54% of the 50 patients who participated in a pro- gram of dietary counseling and behavior modifica- tion during their adolescence. Recent studies sug- gest that dietary and behavior modification programs offer the most hope for the successful management of obesity (4-6). The encouraging re-

March 1981 OBESITY IN ADOLESCENTS 231

Table 2. M e a n Pat ient Weigh t s and Percent O v e r w e i g h t at Ini t iat ion of Trea tment , Comple t i on of Trea tment , and Fol low-up

Mean weight, lbs (kg) Mean percent overweight

End of treatment Follow-up

Initial period Follow-up Initial Follow-up corrected (8)

Initial/ follow-up difference

Female (N=45)

Male (N = 16)

Total (N = 45)

171.6 164.9 148.8 54.9 23.3 (78.0) (74.9) (67.6)

182.4 194.4 173.5 64.4 14.8 (82.9) (88.4) (78.9)

177.6 177.6 159.5 58.2 (80.7) (80.7) (72.5)

32.5 22.4

22.8 41.6 a

20.2 28.7 29.5 a

ap < 0.001

Table 3. Ind iv idua l Fo l low-up Status of Pat ients Trea ted for Obes i ty (N = 50)

% Over Desired Number of patients, Number of patients, weight raw data (%) corrected data (8) (%)

10 (Normal weight) 15 (30%) 11 (22%) 10-20 (Overweight) 12 (24%) 8 (16%) 20 (Obese) 18 (36%) 26 (52%) Unknown 5 (10%) 5 (10%)

sults in this study cannot be attributed to this specific theraputic modality without a controlled study. Our results do suggest, however, that there may be a subpopulation of obese adolescents who tend to lose weight more easily after participating in such a pro- gram.

The females in this study maintained a greater average weight loss during the follow-up period. However, when changes in height are taken into account, the males appear to be more successful in maintaining a decreased level of obesity. The more realistic self-perception by obese adolescent males in figure drawing studies may be a factor in their greater ultimate success (12).

Follow-up studies of initially successful obesity programs in adults have shown disappointing re- sults (1-3). In contrast, after initially unsuccessful results, our obesity program yielded an encouraging long-term follow-up. Hammer et al. have previously described similar findings in adolescents (13). The adolescent's unique ability to make life-style changes may in part explain these rather encouraging long-

term results. The adolescent's inability to make eat- ing behavior changes until reaching an appropriate level of psychologic maturity may in part explain our disappointing initial results.

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13.