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Journal of the American College of Nutrition, Vol. 25, No. 6, 493-501 (2006)
Published by the American College of Nutrition

Eight-Year Longitudinal Changes in Body Composition in Healthy Swiss Adults

Ursula G. Kyle, MS, RD, Katarina Melzer, MS, Bengt Kayser, MD, PhD, Michel Picard-Kossovsky, MD, Gerald Gremion, MD and Claude Pichard, MD, PhD

Clinical Nutrition (U.G.K., K.M., C.P.)
Clinical Nutrition, Internal Medicine (M.P.-K.)
Geneva University Hospital, Institute of Movement Science and Sports Medicine, Faculty of Medicine, University of Geneva (B.K.)
Geneva, Orthopedics, Lausanne University Hospital, Lausanne (G.G.), SWITZERLAND

Address correspondence to: Claude Pichard, MD, PhD, Head, Clinical Nutrition, Geneva University Hospital, 1211 Geneva, SWITZERLAND. E-mail: claude.pichard{at}medecine.unige.ch


   ABSTRACT
TOP
 FOOTNOTES
 ABSTRACT
INTRODUCTION
 SUBJECTS AND METHODS
 RESULTS
 CONCLUSION
 ACKNOWLEDGMENTS
 REFERENCES
 
Objective: Significant changes in body composition occur during lifetime. This longitudinal study (8.0 ± 0.8 yrs) in a cohort of healthy sedentary and physically active men (n = 78) and women (n = 53), aged 20 to 74 yr describes: 1) the longitudinal changes in weight and body composition and 2) their associations with age and physical activity.

Method: Fat-free mass (FFM) and body fat (BF) were assessed by bioelectrical impedance analysis (BIA). Subjects who regularly performed >3 hours per week of endurance type physical activity were classified as "Active". Others were classified as "Sedentary". Subjects were also separated by age (<45 yr vs ≥45 yr).

Results: FFM increased by 1.7 ± 2.8 kg in men <45 yr who gained 4.0 ± 5.0 kg of body weight and was maintained (0.5 ± 1.6 kg) in women <45 y who gained 1.6 ± 3.0 kg of weight. A weight gain of 1.2 ± 3.3 kg in men ≥45 yr was accompanied by stable FFM (–0.1 ± 2.3 kg), and of 1.0 ± 3.2 kg was accompanied by a loss of FFM in women ≥45 yr. In active men ≥45 yr, maintenance of FFM was associated with smaller weight gains than in sedentary; sedentary men ≥45 yr decreased FFM with larger weight gains than active subjects. Sedentary women <45 yr were able to gain FFM; the active women maintained, but did not gain FFM with smaller weight gains than in sedentary women. FFM decreased in ≥45 yr women despite of small weight gains.

Conclusion: Weight change is clearly associated with a change in FFM. Weight gain is necessary to offset age-related FFM loss between 20 and 74 yrs. In active men, a FFM increase was associated with less weight gain than sedentary men. Future studies should evaluate the threshold of weight change and the level of physical activity necessary to prevent age-related losses of FFM.

Key words: bioelectrical impedance analysis (BIA), fat-free mass, body fat, BIA-measured FFM, body composition, longitudinal

Abbreviations: BF = body fat • BMI = body mass index • FFM = fat-free mass


   INTRODUCTION
TOP
 FOOTNOTES
 ABSTRACT
 INTRODUCTION
SUBJECTS AND METHODS
 RESULTS
 CONCLUSION
 ACKNOWLEDGMENTS
 REFERENCES
 
Significant changes in body composition occur during lifetime. Progressive increases in body fat (BF) and decreases in fat-free mass (FFM) during adulthood have been noted [1]. FFM peaks in the fourth decade and decreases thereafter [2]. Excess adiposity or increased body fatness (% BF) are associated with certain chronic diseases, such as cardiovascular disease [3] and increased mortality [4]. On the other hand, FFM declines have been associated with sedentarity [5,6], weakness, disability and morbidity [7–9].

Significant overall weight gains have been recently reported in North American [10] and Europe [11]. Increases in the prevalence in overweight and obesity will also affect the prevalence of excess BF. Weight and body mass index (BMI) alone are not an adequate guide to detect underlying changes in FFM and BF with age and physical activity [7]. Understanding the patterns of weight and body composition changes with aging and the factors that influence body composition can help elucidate the effects that excess body fat or inadequate muscle mass may have on morbidity and mortality.

There is little information available on longitudinal changes in FFM, BF and % BF and the composition of longitudinal weight loss or weight gain [12–15]. Gallagher et al [16] found that weight stability masked sarcopenia in elderly subjects. Also in elderly subjects, Hughes et al [14] noted small decreases in FFM and they were masked by wide inter-individual variations that were dependent on the magnitude of weight change. Heitmann et al [15] found that weight changes were associated with more unfavorable relative changes in FFM in men than in women, even after considering age-related changes in FFM and the differences in percentage BF between men and women. However, differences between FFM and BF changes in older, compared to younger subjects has not been explored. Previous data [1,17] have shown that mean FFM peaks in 35–44 yr old men and 45–54 yr old women and declined thereafter. It is, therefore, possible that patterns of FFM and BF gain and loss may to be different in subjects <45 yr or ≥45 yr. The stratification of subjects as <45 yr and ≥45 yr, based on these previously noted body composition changes between 40 and 50 yrs of age [1] appears to be warranted.

In addition, regular physical activity has been shown to prevent body mass gain, and physical inactivity is a risk factor for body mass gain and obesity among adults [6,18]. Thus, the separate evaluation of physically active and sedentary is also warranted.

The purpose of this 8 yr longitudinal study in a cohort of healthy sedentary and physically active men and women, aged 20 to 74 yr was to determine: 1) the longitudinal changes in weight and body composition and 2) the associations of age and physical activity on the longitudinal changes in body composition.


   SUBJECTS AND METHODS
TOP
 FOOTNOTES
 ABSTRACT
 INTRODUCTION
 SUBJECTS AND METHODS
RESULTS
 CONCLUSION
 ACKNOWLEDGMENTS
 REFERENCES
 
Subjects
Healthy adults were recruited by offering free BIA on an exhibition stand at trade fairs and fun runs and among public employees. Subjects (78 men and 53 women), aged 20–73 yrs were included in the study if they were measured at least twice at an interval of 7 to 9 yrs. All subjects were healthy Caucasians (Western European). Subjects were excluded if they had a doctor visit for "illness" or were hospitalized within 6 months prior to the BIA measurement. Subjects with water or electrolyte imbalances (such as edema, ascites), skin abnormalities (e.g. pachydermia secondary to hypothyroidism) and abnormal body geometry (such as amputation, limb atrophy) that might interfere with BIA measurements, were excluded. Subjects were stratified as <45 yr and ≥45 yr, based on previously noted body composition changes between 40 and 50 yrs of age [1].

The protocol to perform bioelectrical impedance analysis measurements and obtain physical activity, health status, and medication data was approved by the Geneva University Hospital Ethics Committee, and study subjects gave written informed consent.

Anthropometric Measurements and Bioelectrical Impedance Analysis
Body height was measured to the nearest 0.5 cm and body weight to the nearest 0.1 kg on a balance beam scale. Subjects were in indoor clothing without shoes.

FFM and BF were assessed by bioelectrical impedance analysis as previously described [19]. Standardized conditions [2–4] with regard to body position, previous physical exercise, dietary or fluid intake and skin temperature were observed. Measurements were performed at the same time of day in each subject. In case of the participants to the Geneva fun run, BIA was measured before the race. Whole-body resistance (R) was measured with surface electrodes placed on the right wrist and ankle. Briefly, an electrical current of 50 kHz and 0.8 mA was produced by a generator (Bio-Z2® (Spengler, Paris, France; RJL Systems, Clinton Twp) and applied to the skin using adhesive electrodes (3M Red Dot T, 3M Health Care, Borken, Germany) with the subject lying supine [20]. The skin was cleaned with 70% alcohol before application of the contact electrodes, as previously described [19,21].

FFM was determined by the previously validated Geneva bioelectrical impedance analysis equation [21]. FFM (kg): –4.104 + (0.518 * height2 (cm)/resistance ({Omega})) + (0.231 * weight (kg)) + (0.130 * reactance ({Omega})) + (4.229 * sex (with men = 1, women = 0)). This equation was validated against dual-energy x-ray absorptiometry (Hologic QDR-4500, whole body version 8.26a:3) [21] in adults (n = 343, age 20 to 94 yr) and further validated in healthy elderly subjects (n = 206, age 65 to 94 yrs) [22].

Physical Activity
Subjects completed a brief questionnaire about the number of hours per week and the type, frequency and intensity of their physical activity during the last 4 seasons to take into account the seasonal effect on physical activity in Switzerland. The subjects who performed >3 hours per week of endurance type physical activity, including but not limited to jogging, tennis, gymnastics, skiing and swimming on a regular basis were classified as "Active." The follow-up physical activity category was used to classify subjects. Only physical activity with an intensity code of 4.0 or more as defined by the activity intensity codes classified by the Minnesota Leisure Time Activities Questionnaire [23] were counted. Subjects who reported less than 3 hours of physical activity per week were classified as "Sedentary", as previously reported by our group [5,6].

Statistics
The statistical analysis program StatView, version 5 (Abacus Concepts, Berkeley, CA) was used for statistical analysis. The results are expressed as mean ± standard deviation (x ± SD). Paired and unpaired t-tests were used to identify differences in FFM, BF and % BF by age group (<45 yr versus ≥45 yr), sex and physical activity level. The differences between weight gain and loss categories were analyzed by analysis of variance (ANOVA), with post-hoc Bonferroni test after one factor analysis. A two-factor ANOVA was used to test for interaction between age, sex and activity and FFM or BF.

In addition, categorical variables were created for relative changes in weight and FFM by using a cutoff of >3%. This cutoff point was based on the reported coefficient of variation for bioelectrical impedance analysis-determined FFM and a change >3% was unlikely to represent only measurement error. For consistency, the change in weight was categorized by using the same cutoff value. Chi2 was used to test differences in incidence of body composition loss, maintenance or gain. Simple regression analysis was used to determine association between weight or FFM change, weight change and FFM change and age. Stepwise multiple regression analysis was used to determine the effects of gender, age, physical activity and baseline body composition parameters on changes in FFM and weight. Statistical significance was set at p < 0.05 for all tests.


   RESULTS
TOP
 FOOTNOTES
 ABSTRACT
 INTRODUCTION
 SUBJECTS AND METHODS
 RESULTS
CONCLUSION
 ACKNOWLEDGMENTS
 REFERENCES
 
Changes in Body Weight
Significant increases in body weight and BMI were noted both in men and women at follow-up (Table 1). BMI increases were similar in men (1.2 ± 1.5 kg/m2) and women (1.0 ± 1.1 kg/m2, p 0.450). Weight was significantly higher in men than in women (Table 2). The weight increases, both absolute and as percent change, were lower in ≥45 yr than <45 y men or women (Table 2). Sedentary women ≥45 yr maintained weight, whereas active women continued to gain weight (Table 3).


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  		Table 1. Subject Characteristics at Time Baseline and Follow-Up Evaluations

 

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  		Table 2. Longitudinal Body Composition Changes in Men <45 y (n = 50) and ≥45 y (n = 28), and Women <45 yr (n = 35) and ≥45 yr (n = 18)

 

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  		Table 3. Comparison of Estimated Changes in Body Composition Parameters, Extrapolated to One Decade, in Sedentary and Men and Women

 
Changes in Fat-Free Mass and Body Fat
FFM increased in men <45 yr who gained weight (Table 2). Men ≥45 yr and women <45 yr had stable FFM with weight gains of >1.2 kg. A weight gain of 1.0 ± 3.2 kg in women ≥45 yr was accompanied by stable FFM. The weight and FFM changes were greater in men <45 than in women <45 yr both as a percentage of baselines and as a change/yr. In spite of weight gain noted in ≥45 yr men and women, FFM was stable in men and decreased in women ≥45 yr. BF changes were greater in men <45 yr and women ≥45 yr than in men ≥45 yr and women <45 yr (Table 2).

Physical Activity
Longitudinal changes in FFM and BF in sedentary versus active subjects were variable depending on weight gain (Fig 1). Weight gain was associated with maintenance or gain of FFM in <45 yr sedentary men and active men and ≥45 yr active men (Fig 1). Sedentary men ≥45 y were unable to maintain FFM with a weight gain of 3.2 kg. Active <45 yr and sedentary and active ≥45 yr women were also unable to maintain FFM with weight gains of –0.5 to 1.7 kg. The ANOVA for FFM change, which included sex, age and activity, was significant only for age (<45 versus ≥45 yr: p < 0.001). There was no interaction between the main effects. The ANOVA for BF change was significant only for the interaction between sex and activity (p 0.02). The ANOVA for weight change was significant for age (<45 versus ≥45 yr: p 0.03) and sex (p 0.02). There was no interaction between the main effects.


Figure 1
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  		Fig. 1. Longitudinal changes (mean 8-yr) in fat-free mass (FFM) (black bars) and body fat (BF) (gray bars) in sedentary (S) and active (A) men and women aged <45 and ≥45 y. Differences were significant for FFM in sedentary versus active women <45 yr (p = 0.02); active men vs active women <45 yr (p = 0.007); and <45 yr vs ≥45 yr active men (p = 0.02) and sedentary women (p = 0.01; and for BF in sedentary vs active men ≥45 yr. The ANOVA for FFM, which included sex, age and activity, was significant only for age (<45 versus ≥45 yr: p < 0.001). There was no interaction between the main effects. The ANOVA for BF was significant only for the interaction between sex and activity (p 0.02). The ANOVA for weight was significantly for age (<45 versus ≥45 yr: p 0.03) and sex (p 0.02). There was no interaction between the main effects.

 
Sedentary women ≥45 yr were more likely to experience a FFM loss than active younger women, and sedentary women <45 yr were significantly more likely to have high FFM (Fig. 2).


Figure 2
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  		Fig. 2. Prevalence of 8-yr change in fat-free mass (FFM) (top) and body fat (BF) (bottom) in sedentary (S) and active (A) men and women aged <45 yr and ≥45 yr. Black bars, loss >3%; gray bars, stable; open bars gain >3%. n = number of subjects. Differences ({chi}2) between sedentary and active were significant for FFM in women <45 yr, {chi}2 8.8, degrees of freedom, 2; p = 0.01; women ≥45 yr, {chi}2 7.9, degrees of freedom, 2; p = 0.01. Differences for BF in sedentary versus active were non-significant.

 
Active men <45 yr had higher FFM gain than sedentary men <45 yr who had higher weight gains (Table 3). FFM gain was greater in sedentary than in active women <45 yr.

Predictors of Changes in Body Weight and Body Composition
When classifying the subjects by weight loss or gain category (Fig. 3), it is noted that weight loss resulted in loss of FFM and weight gain resulted in FFM gain and this is seen in both men <45 yr and ≥45 yr. On the other hand, women ≥45 y who were weight stable or gained weight and women <45 yr who gained weight lost FFM and this is confirmed by the prevalence of 40% of weight-gaining ≥45 yr women losing FFM (Fig. 4). Furthermore it is noted that few men and women ≥45 yr who gained weight also gained FFM (Fig. 4). Weight loss resulted in BF loss and weight gain resulted in BF gain.


Figure 3
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  		Fig. 3. Longitudinal changes (mean 8-yr) in fat-free mass (FFM) (black bars) and body fat (BF) (gray bars) by weight loss category (loss >3%; stable; gain >3%) in <45 yr and ≥45 yr men and women. The ANOVA for FFM, which included sex, age and weight gain category, was significant for weight gain category (p < 0.001) and age (<45 versus ≥45 yr: p = 0.03). There was no interaction between the main effects. The ANOVA for BF was significantly for weight gain category (p < 0.001). There was no interaction between the main effects.

 

Figure 4
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  		Fig. 4. Prevalence of ≥3% loss (black bars), stable (gray bars) or ≥3% gain (open bars) of FFM (top) and BF (bottom) according to 8-yr change in weight (loss >3%, stable, gain >3%). n = number of subjects. Differences ({chi}2) between FFM-losing, stable and gaining subjects were significant in men <45 yr, {chi}2 34.7, degrees of freedom, 4; p < 0.001; women <45 yr, {chi}2 11.2, degrees of freedom, 4; p = 0.02; and between BF-losing, stable and gaining subjects were significant in men <45 yr, {chi}2 22.5, degrees of freedom, 4; p < 0.001; women <45 yr, {chi}2 19.9, degrees of freedom, 4; p < 0.001; women ≥45 yr, {chi}2 15.8, degrees of freedom, 4; p = 0.003.

 
Overall, in the weight loss group, 49% of weight loss was attributed to change in FFM. Among subjects who gained weight, the change in FFM accounted for 32% of the weight change.

Simple regressions between change in FFM and change in weight (Table 4) show that, with weight maintenance, men would lose 0.12 kg FFM over the follow-up period, whereas women would lose 0.29 kg. Additionally, it indicates that a gain or loss of 1 kg body weight is associated with a gain or loss of FFM of 0.40 kg in men and 0.26 kg in women. Multiple regressions showed that change in FFM was significantly predicted by weight change and age (Table 4). Together they explained 47% of the variance in FFM changes over the follow-up period. FFM changes were unrelated to baseline weight, gender or activity level. Multiple regressions also showed that weight change was independently and inversely predicted only by baseline % BF (Table 4). Weight change was not significantly associated with baseline age, baseline weight, gender or activity level.


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  		Table 4. Simple and Stepwise Multiple Regression for Change in Fat-Free Mass and Body Weight in Men and Women during 8-Year Follow-Up

 

   DISCUSSION
 
This study assessed the patterns of changes in FFM and BF over an average of 8 yrs in men and women aged <45 yr and ≥45 y, classified as sedentary or active. Our study showed that body weight gain is positively associated with FFM maintenance and has an influence on age-related FFM loss. Physical activity exerted a significant effect on both FFM and BF.

Changes in Body Mass
Significant increases in body weight and BMI were noted both in active and sedentary men and women during the follow-up period. The weight increase after 45 y continued at a lower rate than in younger men. Weight gain in <45 yr old was lower in women than in men and the gain was lower in active than in sedentary women.

BMI increases were somewhat smaller in men (<45 yr: 0.17/y; ≥45 y 0.10/y) than BMI increases reported in US men [24] (<45 yr: 0.20; ≥45 yr 0.12) and in women (<45 y 0.12/y; ≥45 yr: 0.15/y) compared to US women (<45 yr: 0.16/y; ≥45 yr: 0.18/y). A BMI increase of about 1.0–1.7 kg/m2 per decade would lead to significant weight increases in Swiss adults and would suggest that the prevalence of overweight is likely to increase in the future in Swiss adults, as has been noted in other European countries [25] and confirms population trends in Switzerland [26,27].

Changes in FFM
Our study shows a clear association between weight gain and FFM gain. Weight-gaining subjects were able to maintain FFM, as long as weight-related FFM gain was greater than age-related FFM loss. In active men, a smaller gain in weight was necessary to maintain FFM than in sedentary subjects, and this is noted in both men <45 yr and ≥45 yr. The lower weight gain in women than in men resulted in a loss of FFM in women, except in sedentary women <45 yr. Thus, women ≥45 yr were vulnerable to FFM loss even with weight gain.

The % FFM change per kg weight change was greater in men than in woman, which suggests greater loss or gain of FFM in men than in women. Visser et al [28] and Gallagher et al [16] also reported greater loss of absolute lean mass in older men than in women. In our study over a longer period of time, sedentary men increased their FFM, whereas active women <45 yr who gained less weight lost FFM. This suggests that the weight-related increase in FFM in sedentary women was greater than age-related loss in FFM.

We found that FFM changes were larger in our men and women (Table 2) than those reported in US men and women [24] (men: <45 yr: 0.08 ± 0.45 kg/yr; ≥45 yr; –0.13 ± 0.63 kg/yr; women: <45 yr: 0.04 ± 0.57 kg/yr; ≥45 yr: 0.0 ± 0.56 kg FFM/yr). The larger gain in FFM in <45 yr and the smaller loss of FFM in ≥45 yr per year might be related to higher physical activity levels in our subjects, since 69% reported ≥3 h physical activity per week. Visser et al [28] and Gallagher et al [16] have reported loss of appendicular skeletal muscle mass, which was masked by simultaneous gain in body fat.

Predictors of Changes in Body Weight and Body Composition
Weight change is clearly associated with a change in FFM [14,29]. There was a moderate correlation between weight change and FFM change (r – 0.60, p < 0.001). Multiple regressions confirmed that FFM change was significantly predicted by weight change and age (p < 0.001).

Age is a significant predictor of FFM change in men (r = 0.34, p < 0.002), but not in women (r = 0.25, p < 0.07). The age-related longitudinal changes in FFM (based on linear regression between FFM and age) were –0.9 kg/decade for men and –0.4 kg/decade for women. This is lower than the FFM changes reported in cross-sectional studies of –1.5 kg/decade in men and –0.8 kg/decade in women [30] and longitudinal changes of –1.2 and –0.1 kg FFM per decade in weight-stable elderly men and women, respectively [14]. Our results suggest that the decreases in FFM/decade are smaller in younger subjects than in subjects ≥45 yr, because higher weight gains in younger subjects contributed to greater gains in FFM than in older subjects. Thus weight-related FFM gains partially offsets the age-related FFM loss in our study. However, we are unable to determine the threshold of weight gain necessary to maintain FFM during aging from our data.

The active men were able to increase their FFM with less weight gain than sedentary men. The active men ≥45 yr were also able to maintain FFM with smaller gains in weight, whereas FFM decreased in sedentary men ≥45 yr that had larger weight gains. Sedentary women <45 yr were able to gain FFM, whereas the active maintained, but did not gain FFM with smaller weight gains than noted in sedentary woman. FFM decreased in ≥45 yr women despite of small gain in weight. These results suggest that physical activity influences the FFM changes with age. Our results also indicate, as suggested by Forbes [31], that physical activity does not prevent FFM loss if weight loss occurs in physically active subjects as a result of an energy deficit.

In healthy subjects, higher FFM has been reported in obese subjects, because more FFM is required to carry excess body weight [32]. Higher FFM appears to be beneficial, especially in older subjects, because it represents greater FFM reserves in case of illness and protects from negative effects of low FFM. Low FFM is a major contributor to the loss of functional ability and health [33]. Further research is necessary to determine the threshold of where high BF outweighs the benefit of high FFM.

Multiple regression analysis (Table 4), however, did not show a significant association between physical activity and FFM change. Our study, therefore, indicated that endurance training is not an independent predictor of changes in FFM. This may be due the fact that physical activity in our study was below the threshold of ≥1 hour of physical activity per day or that the physical activity levels of greater than 1.4–1.6 times the basal metabolic rate are necessary for physical activity to show an effect on weight or BMI and body composition [34]. However, resistance training does appear to lower the loss of lean tissue with age [35].

It has been previously shown that there is an inverse relation between physical activity and body fatness, and that body fat reserves change with structured physical activity [36,37]. Because physical activity affects body weight, changes in FFM with age are also influenced by physical activity-related weight changes [18,38,39]. Furthermore, physical activity behavior may differ in subjects with varying levels of obesity [40,41]. The non-significant association between physical activity and FFM change in the multiple regression analysis suggests that physical activity levels of 3 hours per week (30 minutes most days of the week) [42], representing 150–200 kcal/day of energy expenditure due to physical activity are inadequate to have a significant effect on body composition. Further research is necessary to determine if physical activity levels of 1.75 times the resting metabolic rate, as recommended by the World Health Organization [43] would have an effect on body composition.

Study Limitations
Limitations of this study are that no information was available about tobacco use or hormone replacement therapy in women. The subjects were volunteers in good health and their body weight was comparable to those reported by Swiss population studies [26], but were not randomly selected and may therefore not be strictly representative of the general population.

The results of the study might have been affect by changes in activity level in the 8-year follow-up period. We classified the subject as "active" or "sedentary" based on the most recent physical activity questionnaire. Thus subjects who were active, but became sedentary would be classified as sedentary and vice versa. Review of follow-up data during the course of the 8-year study period shows that most active subjects remained active throughout the study period and less than 10% of subjects changed activity level classification. We believe that changes in activity level during the course of the study did not affect the results.

With regard to BIA measurements, standardized conditions with regard to body position, previous exercise, dietary intake and skin temperature must be respected [44–46]. Consumption of food and beverage may decrease impedance by 4 to 15 {Omega} over a 2 to 4 h period after meals, representing an error smaller than 3% [44,46]. We did not correct for subjects not having eaten for 4 hours prior to the measurement. The effects of food and beverage have been shown to be small and would not have significantly altered the results because measurements were performed at the same time of day [47].


   CONCLUSION
TOP
 FOOTNOTES
 ABSTRACT
 INTRODUCTION
 SUBJECTS AND METHODS
 RESULTS
 CONCLUSION
ACKNOWLEDGMENTS
 REFERENCES
 
This longitudinal study showed significant gains in weight, BMI and BF over 8 years and demonstrated that body weight change is clearly associated with a FFM change. Weight gain is necessary to offset age-related FFM loss between 20 and 74 yrs. In active men, a FFM increase was associated with less weight gain than sedentary men. The active women maintained, but did not gain FFM with smaller weight gains than in sedentary woman. Future studies should evaluate the threshold of weight change and the level of physical activity necessary to prevent age-related losses of FFM.


   ACKNOWLEDGMENTS
TOP
 FOOTNOTES
 ABSTRACT
 INTRODUCTION
 SUBJECTS AND METHODS
 RESULTS
 CONCLUSION
 ACKNOWLEDGMENTS
REFERENCES
 
We thank the Foundation Nutrition 2000Plus for its financial support.


   FOOTNOTES
TOP
 FOOTNOTES
ABSTRACT
 INTRODUCTION
 SUBJECTS AND METHODS
 RESULTS
 CONCLUSION
 ACKNOWLEDGMENTS
 REFERENCES
 
Sponsorship: Foundation NutritionPlus2000

Received December 7, 2004. Revised December 19, 2005.
   REFERENCES
TOP
 FOOTNOTES
 ABSTRACT
 INTRODUCTION
 SUBJECTS AND METHODS
 RESULTS
 CONCLUSION
 ACKNOWLEDGMENTS
 REFERENCES
 

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