Original Communication

European Journal of Clinical Nutrition (2005) 59, 137–141. doi:10.1038/sj.ejcn.1602061 Published online 29 September 2004

Central and total adiposity are lower in overweight and obese children with high cardiorespiratory fitness

Guarantors: GP Nassis and LS Sidossis.

Contributors: GPN and LSS developed the original idea. GPN and GP collected the data and performed the analysis. GPN drafted the paper; LSS and GP contributed to the interpretation of data and to the writing of the paper.

G P Nassis1,2, G Psarra2 and L S Sidossis2

  1. 1Department of Sport Medicine and Biology of Physical Activity, Faculty of Physical Education and Sport Science, University of Athens, Daphne, Greece
  2. 2Laboratory of Nutrition and Clinical Dietetics, Department of Nutrition and Dietetics, Harokopio University, Athens, Greece

Correspondence: LS Sidossis, Laboratory of Nutrition and Clinical Dietetics, Department of Nutrition and Dietetics, Harokopio University, 70 El. Venizelou street, 176 71 Athens, Greece. E-mail: lsidossis@hua.gr

Received 2 February 2004; Revised 7 July 2004; Accepted 4 August 2004; Published online 29 September 2004.

Top

Abstract

Objective: To examine the influence of cardiorespiratory fitness on total and truncal fatness in children. It was hypothesised that high cardiorespiratory fitness would result in lower total and central obesity.

Design: Observational cohort study.

Setting: Primary and secondary schools in Athens, Greece.

Subjects: A total of 1362 healthy children aged 6–13 y (742 boys and 620 girls).

Methods: Anthropometric data (height, body mass, four skinfolds thickness) were collected and per cent body fat was calculated. Body mass index (BMI) sex- and age-specific cutoff points were used for overweight and obesity definition and children were placed in two groups: overweight/obese and nonoverweight. Cardiorespiratory fitness (CRF) was assessed with the endurance shuttle-run test. Participants were grouped into high (upper two quintiles) and low (lower two quintiles) CRF based on age and sex distributions. T-test and Mann–Whitney test were used for comparisons between fit and unfit children within each BMI category.

Results: Sum of skinfolds, subscapular and truncal skinfold thickness, BMI and per cent body fat were lower in overweight and obese youths with high CRF in comparison with youths at the same BMI category with low CRF (P<0.01). The beneficial effect of high CRF was also presented in nonoverweight children (P<0.01). The influence of CRF on body composition remained even after correcting body fatness for BMI.

Conclusions: Central and total obesity were lower in overweight and obese children with high CRF. This is the first study to show that a high CRF may reduce the hazards of obesity in children.

Sponsorship: None.

Keywords:

central adiposity, fatness, fitness, obesity, children

Top

Introduction

The prevalence of paediatric obesity has been increased in USA and Europe over the past years (Wang et al, 2002; Lobstein & Frelut, 2003). It seems, however, that central and abdominal obesity increase at a faster rate than total body obesity in children (McCarthy et al, 2003). Truncal skinfold thickness is an index of central adiposity in children (Freedman et al, 1989, 1999; Goran et al, 1995). Goran et al (1995) have shown that individual trunk skinfold measures are associated with intra-abdominal adipose tissue in preadolescent children.

Central adiposity is associated with multiple risk factors for cardiovascular disease in both children (Freedman et al, 1999; Savva et al, 2000; Maffeis et al, 2003) and adults (Bigaard et al, 2003). In men and women, there is strong evidence that physical activity and cardiorespiratory fitness (CRF) may protect from the adverse effects of obesity on health. Indeed, Blair et al (1989) reported more than two-fold lower relative risk of all-cause mortality in obese adults with moderate and high fitness compared with obese with low fitness adults. Recently, Ross and Katzmarzyk (2003) reported that high CRF was associated with lower levels of total and central obesity for a given body mass index (BMI) in 20–59 y of age men and women.

To the authors' best knowledge, there is no information in the literature on the effect of CRF on total and central obesity in children. Therefore, the aim of the present study was to examine the influence of CRF on total body and central fatness in a sample of young people.

Top

Methods

Participants

A total of 1362 healthy children (742 boys and 620 girls) aged 6–13 y participated in this study. Subjects were living in Athens, Greece, and a signed consent was obtained from their parents. Approval to conduct the study was granted by the Bioethics Committee of Harokopio University, Athens, Greece.

Anthropometric measurements

All anthropometric data were obtained following standard procedures (Heyward & Stolarczyk, 1996). Standing height was measured to the nearest 0.1 cm with a stadiometer while children were standing barefoot. Body mass was determined to the nearest 0.1 kg using a balance scale with the subject in light clothing. BMI was calculated as body mass (kg) divided by height (m) squared. Skinfold thickness was measured using a Harpenden skinfold caliper (British Indicators Ltd, London, UK) to the nearest 0.2 mm at the triceps, biceps, subscapular and suprailiac sites (Heyward & Stolarczyk, 1996). All measurements were taken 3 times on the right side of the body and the mean value is reported. All four sites' skinfold thicknesses were summed to provide the sum of skinfolds. Subscapular skinfold and the sum of two trunk skinfolds (subscapular and suprailiac) were used as an index of central obesity. Finally, per cent (%) body fat was estimated from triceps and subscapular skinfolds (Slaughter et al, 1988). The technical error of measurement (Ulijaszek & Kerr, 1999) from repeated measures taken by the two experimenters in 12 subjects was 0.347 cm for height, 0.205 kg for body mass, 0.776 mm for triceps, 0.705 mm for biceps, 0.505 mm for subscapular and 0.853 mm for suprailiac skinfold thickness.

Participants were classified into two groups (nonoverweight and nonobese simply stated as nonoverweight and overweight/obese) according to their BMI. The age- and sex-specific BMI cutoff points for overweight were used (Cole et al, 2000). The cutoff values for 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5 and 13 y of age were 17.6, 17.7, 17.9, 18.2, 18.4, 18.8, 19.1, 19.5, 19.8, 20.2, 20.6, 20.9, 21.2, 21.6, 21.9 kg/m2, respectively, for boys and 17.3, 17.5, 17.8, 18.0, 18.3, 18.7, 19.1, 19.5, 19.9, 20.3, 20.7, 21.2, 21.7, 22.1, 22.6 kg/m2, respectively, for girls (Cole et al, 2000).

CRF assessment

CRF was assessed with the endurance 20-m shuttle-run test (Council of Europe, 1993). In this test, children run back and forth between two lines, 20 m apart. The running pace was given by an audiotape. Running speed was 8.0 km/h at the start of the test and increased by 0.5 km/h every minute. Children were instructed to complete as many stages as possible. The test was stopped when the child was unable to reach the 3 m zone placed ahead of each 20 m line at the moment of the audio signal, two times consecutively. The result was recorded with an accuracy of every completed stage (Council of Europe, 1993). The shuttle-run test is regarded as a valid tool for the evaluation of maximum oxygen uptake in children (Leger & Lambert, 1982; Mechelen Van et al, 1986). TEM for repeated measures in 12 subjects was 0.122 stages. The mean difference for repeated shuttle-runs by 55 participants of the present study was 0.13 stages, while 95% confidence intervals were -0.13 and 0.39 stages, respectively (Bland & Altman, 1986). Children were divided into quintiles based on age- and sex-specific distributions for CRF. Participants were classified as unfit (first and second quintile) or fit (fourth and fifth quintile). The middle quintile was not used in the analysis.

Statistical analysis

Individual values for subscapular skinfold, sum of four skinfolds, sum of truncal skinfolds and per cent body fat were divided by BMI to adjust for different BMIs. Normality of distribution was checked for all variables. Differences between fit and unfit children within each BMI category were assessed with t-test for independent samples (all variables for the overweight and obese children; % body fat for the nonoverweight) and Mann–Whitney U-test (subscapular skinfold, sum of skinfolds and sum of trunk skinfolds for the nonoverweight children). The relationship between CRF and BMI was tested with the Pearson correlation coefficient. A P level of 0.05 was used as criterion of statistical significance. Statistical analysis was completed with SPSS software (version 10.0 for Windows). Absolute and not adjusted values are shown in figures for clarity of presentation. Values are presented as meansplusminuss.d.

Top

Results

Participants' anthropometric and physical characteristics are presented in Table 1. The mean age of the sample was 10.9plusminus1.6 y for the nonoverweight group and 10.8plusminus1.6 y for the overweight/obese group. Height did not differ between fit and unfit children in both groups.


In all, 472 children (34.8%) were overweight and obese. Subscapular and truncal skinfold thicknesses were significantly lower (P<0.01) in overweight/obese and fit children compared with unfit children at the same BMI category (Figure 1). The adjusted values were 0.55plusminus0.18 and 0.72plusminus0.21 mm per kg/m2 for the subscapular skinfold thickness (t=5.95, P<0.01) and 1.39plusminus0.45 and 1.77plusminus0.44 mm per kg/m2 for truncal skinfolds (t=6.09, P<0.01) for fit and unfit children, respectively. Similarly, both subscapular skinfold thickness and truncal skinfolds were lower in fit compared with unfit nonoverweight children (P<0.01).

Figure 1.
Figure 1 - Unfortunately we are unable to provide accessible alternative text for this. If you require assistance to access this image, please contact help@nature.com or the author

Subscapular skinfold thickness (a) and sum of trunk skinfolds (b) for the nonoverweight and overweight/obese children with high (fit) and low (unfit) CRF (meansplusminuss.d.). # P<0.01 between fit and unfit within the same BMI category.

Full figure and legend (19K)

CRF favourably affected the sum of skinfolds and per cent body fat (P<0.01) in both overweight and nonoverweight children (Figure 2). The adjusted values for overweight/obese fit and unfit children were: 2.74plusminus0.68 and 3.34plusminus0.63 mm per kg/m2 for the sum of skinfolds (t=6.40, P<0.01) and 1.17plusminus0.24 and 2.14plusminus0.24% per kg/m2 for the body fat (t=5.08, P<0.01), respectively. Finally, CRF was correlated with BMI in the whole group of subjects (r=-0.272, P<0.001).

Figure 2.
Figure 2 - Unfortunately we are unable to provide accessible alternative text for this. If you require assistance to access this image, please contact help@nature.com or the author

Sum of skinfolds (a) and per cent body fat (b) for the nonoverweight and overweight/obese children with high (fit) and low (unfit) CRF (meansplusminuss.d.). # P<0.01 between fit and unfit within the same BMI category.

Full figure and legend (19K)

Top

Discussion

The main finding of the present study was that BMI, sum of four skinfolds, subscapular and truncal skinfolds thickness and per cent body fat were lower in overweight and obese children with high CRF in comparison with children at the same BMI category with low CRF. The beneficial influence of high CRF on body composition remained even after the values of body fatness were corrected for different BMIs.

This is the first study to show the favourable effect of high CRF on body fat distribution in overweight and obese children. Although participants were not randomly selected, prevalence of overweight and obesity was similar with representative samples of Greek children (31% overweight children in representative samples; 34.8% in our study; Lobstein & Frelut, 2003). Prevalence of overweight and obesity in the present study was also within the range reported for the countries surrounding the Mediterranean (27–36% for children aged 7–11 y; Lobstein & Frelut, 2003). CRF was assessed indirectly. However, the validity of the endurance shuttle-run test in estimating maximal aerobic capacity has been shown to be high in children (Leger & Lambert, 1982; Mechelen Van et al, 1986); its repeatability has also been shown to be high in a subgroup of participants of the present study. Furthermore, our study was limited to the use of anthropometric indices. Highly sophisticated methods, such as computed tomography and magnetic resonance imaging, could add more information on the role of cardiovascular fitness in intra-abdominal fat in children. However, these methods are not suitable for large population studies.

The results of the present study are in agreement with those reported for adult men and women (Ross & Katzmarzyk, 2003). These authors showed that waist circumference, sum of trunk skinfolds and sum of four skinfolds were lower at a given BMI in individuals with high cardiorespiratory fitness. The diminished central obesity in the group with high CRF in the present study is also consistent with previous intervention studies showing a reduction in waist circumference and intra-abdominal fat after exercise training, independently of BMI changes (Mourier et al, 1997; Ross et al, 2000).

Central fatness has been shown to increase at a faster rate than total body fat in a sample of European children (McCarthy et al, 2003). Increased accumulation of adipose tissue in the abdominal or central region of children and adolescents is associated with adverse concentrations of lipids and insulin. Indeed, subscapular and truncal skinfold thickness and waist circumference are associated with elevated fasting insulin, LDL cholesterol, total cholesterol and triglycerides levels (Freedman et al, 1999; Savva et al, 2000). These body composition indices are also related to increased systolic and diastolic pressure (Savva et al, 2000; Maffeis et al, 2003) and decreased HDL cholesterol concentration in children (Freedman et al, 1999).

It is not possible to estimate the impact of the findings of the present study on the future health complications of obesity in children. In adults, however, it has been shown that fit men with elevated central adiposity had almost 2.5 times lower mortality rate than did the unfit men in the same central adiposity category (Lee et al, 1999). In addition, fit men with high waist circumference had a rate of all-cause mortality similar to unfit men with low waist circumference both in a USA (Lee et al, 1999) and in a European sample (Lakka et al, 2002). In another study, odds ratios for metabolic diseases were increased in overweight men and women with high abdominal adiposity compared with men and women with normal abdominal adiposity (Janssen et al, 2002). Finally, overweight and obese men and women with high CRF had almost 2.5-fold lower relative risk for all-cause mortality compared with individuals at the same BMI category with low CRF (Blair et al, 1989).

The mechanism by which high CRF reduces the hazard risk of obesity is not clear. Cardiovascular fitness is inversely related to systolic and diastolic pressure, triglycerides and total cholesterol concentration; it is also positively associated with HDL cholesterol in children (Tell & Vellar, 1988). In adults, regular exercise is associated with improvement in muscle metabolism and thus a reduction in metabolic risk (Duncan et al, 2003; Goodpaster et al, 2003).

In conclusion, overweight and obese children with high CRF presented lower BMI, sum of skinfolds, subscapular and truncal skinfold thickness and per cent body fat compared with children at the same BMI category with low CRF. The beneficial impact of high CRF on body composition remained even after the values of body fatness were corrected for different BMIs. These novel findings indicate that being fit may reduce the hazards of obesity in paediatric population. They also highlight the limitation in examining health complications of obesity by studying BMI alone and suggest that truncal adiposity, per cent fat and CRF should also be used in clinical practice. Future studies should be conducted in representative samples by using direct measures of body fat distribution, such as computed tomography and magnetic resonance imaging. In addition, potential gender differences on the effect of fitness on total and central obesity would be of great clinical significance and this issue remains open to further investigation.

Top

References

  1. Bigaard J, Tjonneland A, Thomsen BL, Overvad K, Heitmann BL & Sorensen TI (2003): Waist circumference, BMI, smoking, and mortality in middle-aged men and women. Obes. Res. 11, 895–903. | PubMed | ISI |
  2. Blair SN, Kohl HW, Paffenbarger RS, Clark DG, Cooper KH & Gibbons LW (1989): Physical fitness and all-cause mortality: a prospective study of healthy men and women. JAMA 262, 2395–2401. | Article | PubMed | ISI | ChemPort |
  3. Bland J & Altman D (1986): Statistical methods for assessing agreement between two methods of clinical measurement. Lancet 1, 307–310. | PubMed | ISI | ChemPort |
  4. Cole TJ, Bellizi C, Flegal KM & Dietz WH (2000): Establishing a standard definition for child overweight and obesity worlwide: international survey. BMJ 320, 1240–1243. | Article | PubMed | ChemPort |
  5. Council of Europe, Commitee for the Development of Sport (1993): EUROFIT: Handbook for the EUROFIT Tests of Physical Fitness. Strasbourg, France: Council of Europe.
  6. Duncan GE, Perri MG, Theriaque DW, Hutson AD, Eckel RH & Stacpoole PW (2003): Exercise training, without weight loss, increases insulin sensitivity and postheparin plasma lipase activity in previously sedentary adults. Diabetes Care 26, 557–562. | PubMed | ChemPort |
  7. Freedman DS, Srinivasan SR, Harsha DW, Webber LS & Berenson GS (1989): Relation of body fat patterning to lipid and lipoprotein concentrations in children and adolescents: the Bogalusa Heart Study. Am. J. Clin. Nutr. 50, 930–939. | PubMed | ISI | ChemPort |
  8. Freedman DS, Serdula MK, Srinivasan SR & Berenson GS (1999): Relation of circumferences and skinfold thicknesses to lipid and insulin concentrations in children and adolescents: the Bogalusa Heart Study. Am. J. Clin. Nutr. 69, 308–317. | PubMed | ISI | ChemPort |
  9. Goodpaster BH, Katsiaras A & Kelley DE (2003): Enhanced fat oxidation through physical activity is associated with improvements in insulin sensitivity in obesity. Diabetes 52, 2191–2197. | PubMed | ChemPort |
  10. Goran MI, Kaskoun M & Shuman WP (1995): Intra-abdominal adipose tissue in young children. Int. J. Obes. Relat. Metab. Disord. 19, 279–283. | PubMed | ChemPort |
  11. Heyward VH & Stolarczyk LM (1996): Applied Body Composition Assessment. Champaign, IL: Human Kinetics.
  12. Janssen I, Katzmarzyk PT & Ross R (2002): Body mass index, waist circumference, and health risk: evidence in support of current National Institutes of Health guidelines. Arch. Intern. Med. 162, 2074–2079. | Article | PubMed | ISI |
  13. Lakka HM, Lakka TA, Tuomilehto J & Salomen JT (2002): Abdominal obesity is associated with increased risk of acute coronary events in men. Eur. Heart J. 23, 687–689. | Article | PubMed |
  14. Lee CD, Blair SN & Jackson AS (1999): Cardiorespiratory fitness, body composition, and all-cause and cardiovascular disease mortality in men. Am. J. Clin. Nutr. 69, 373–380. | PubMed | ISI | ChemPort |
  15. Leger LA & Lambert J (1982): A maximal multistage 20-m shuttle run test to predict VO2max. Eur. J. Appl. Physiol. 49, 1–12. | ChemPort |
  16. Lobstein T & Frelut ML (2003): Prevalence of overweight among children in Europe. Obes. Rev. 4, 195–200. | Article | PubMed | ChemPort |
  17. Maffeis C, Corciulo N, Livieri C, Rabbone I, Trifiro G, Falorni A, Guerraggio L, Peverelli P, Cuccarolo G, Bergamaschi G, Di Pietro M & Grezzani A (2003): Waist circumference as a predictor of cardiovascular and metabolic risk factors in obese girls. Eur. J. Clin. Nutr. 57, 566–572. | Article | PubMed | ISI | ChemPort |
  18. McCarthy HD, Ellis SM & Cole TJ (2003): Central overweight and obesity in British youth aged 11–16 years: cross sectional surveys of waist circumference. BMJ 326, 624–627. | Article | PubMed |
  19. Mechelen Van W, Hlobil H & Kemper HCG (1986): Validation of two running tests as estimates of maximal aerobic power in children. Eur. J. Appl. Physiol. 55, 503–506.
  20. Mourier A, Gautier JF, De Kerviler E, Bigard AX, Villette JM, Garnier JP, Duvallet A, Guezennec CY & Cathelineau G (1997): Mobilization of visceral adipose tissue related to the improvement in insulin sensitivity in response to physical training in NIDDM. Effects of branched-chain amino acid supplements. Diabetes Care 20, 385–391. | PubMed | ChemPort |
  21. Ross R & Katzmarzyk PT (2003): Cardiorespiratory fitness is associated with diminished total and abdominal obesity independent of body mass index. Int. J. Obes. Relat. Metab. Disord. 27, 204–210. | Article | PubMed | ChemPort |
  22. Ross R, Dagnone D, Jones PJH, Smith H, Paddags A, Hudson R & Janssen I (2000): Reduction in obesity and related comorbid conditions after diet-induced weight loss or exercise-induced weight loss in men. Ann. Intern. Med. 133, 92–103. | PubMed | ISI | ChemPort |
  23. Savva SC, Tornaritis M, Savva ME, Kourides Y, Panagi A, Silikiotou N, Georgiou C & Kafatos A (2000): Waist circumference and waist-to-hip ratio are better predictors of cardiovascular disease risk factors in children than body mass index. Int. J. Obes. Relat. Metab. Disord. 24, 1453–1458. | Article | PubMed | ChemPort |
  24. Slaughter MH, Lohman TG, Boileau RA, Horswill CA, Stillman RJ, Van Loan MB & Bemben DA (1988): Skinfold equations for estimation of body fatness in children and youth. Hum. Biol. 60, 709–723. | PubMed | ISI | ChemPort |
  25. Tell GS & Vellar OD (1988): Physical fitness, physical activity, and cardiovascular disease risk factors in adolescents: the Oslo Youth Study. Prev. Med. 17, 12–24. | Article | PubMed | ChemPort |
  26. Ulijaszek SJ & Kerr DA (1999): Anthropometric measurement error and the assessment of nutritional status. Br. J. Nutr. 82, 165–177. | PubMed | ChemPort |
  27. Wang Y, Monteiro C & Popkin BM (2002): Trends of obesity and underweight in older children and adolescents in the United States, Brazil, China and Russia. Am. J. Clin. Nutr. 75, 971–977. | PubMed | ISI | ChemPort |

Extra navigation

.

naturejobs

More science jobs
Post a job for free
ADVERTISEMENT