Low fat-free mass (FFM) is a risk factor for morbidity and mortality in elderly and patient populations. T
herefore, measurement of FFM is important in nutritional assessment. Bioelectrical impedance analysis (BIA) is a convenient met
hod to assess FFM and FFM index (FFMI; FFM/
heig
ht
2). Alt
houg
h reference values
have been establis
hed for individuals wit
h normal body weig
ht, no specific cutoff values are available for overweig
ht and obese populations. Also, limited studies accounted for t
he age-related decline in FFM.<
h4 id="absSec_2">Objective
h4>
To determine BMI- and age-specific reference values for abnormal low FFM(I) in white-ethnic men and women free of self-reported disease from the general population.
<
h4 id="absSec_3">Design
h4>
The UK Biobank is a prospective epidemiological study of the general population from the United Kingdom. Individuals in the age category 45 to 69 years were analyzed. In addition to body weight, FFM and FFMI were measured using a Tanita BC-418MA. Also, self-reported chronic conditions and ethnic background were registered, and lung function was assessed using spirometry.
<
h4 id="absSec_4">Results
h4>
After exclusion of all individuals with missing data, nonwhite ethnicity, self-reported disease, body mass index (BMI) less than 14 or 36 kg/m2 or higher, and/or an obstructive lung function, reference values for FFM and FFMI were derived from 186,975 individuals (45.9% men; age: 56.9 ± 6.8 years; BMI: 26.5 ± 3.6 kg/m2; FFMI 18.3 ± 2.4 kg/m2). FFM and FFMI were significantly associated with BMI and decreased with age. Percentiles 5, 10, 25, 50, 75, 90, and 95 were calculated for FFM, FFMI, and fat mass (index), after stratification for gender, age, and BMI.
<
h4 id="absSec_5">Conclusions
h4>
Using the UK Biobank dataset, new reference values for body composition assessed with BIA were determined in white-ethnic men and women aged 45 to 69 years. Because these reference values are BMI specific, they are of broad interest for overweight and obese populations.