Prevalence of normal weight obesity in Switzerland: effect of various definitions.
BACKGROUND
Normal weight obesity (NWO) is defined as an excessive body fat associated with a normal body mass index (BMI < 25 kg/m(2)), but its prevalence in the general population is unknown.


OBJECTIVE
To assess the prevalence of NWO in Switzerland according to different cut points used to define excess body fat.


METHODS
Cross-sectional study including 3,213 women and 2,912 men aged 35-75 years. Body fat was assessed by bioelectrical impedance analysis and prevalence of NWO was assessed using four previously published definitions for excess body fat.


RESULTS
Percent body fat increased with age: in men, the values (mean +/- SD) were 20.2 +/- 5.4, 23.0 +/- 5.4, 26.3 +/- 5.2 and 28.2 +/- 4.6 for age groups 35-44, 45-54, 55-64 and 65-75 years, respectively; the corresponding values for women were 29.9 +/- 7.8, 33.1 +/- 7.4, 36.7 +/- 7.5 and 39.6 +/- 6.9. In men, prevalence of NWO was <1% irrespective of the definition used. Conversely, in women, a 1- to 20-fold difference (from 1.4 to 27.8%) in NWO prevalence was found. The prevalence of NWO increased with age when age-independent cut points were used in women, but not in men.


CONCLUSIONS
Prevalence of NWO is low in the general population and higher in women than in men. The prevalence is highly dependent on the criteria used to define excess body fat, namely in women. The use of gender- and age-specific cut points to define excess body fat is better than fixed or gender-specific only cut points.
Marques-Vidal
Pedro
P
Cardiomet, CHUV, Lausanne, Switzerland. pedro-manuel.marques-vidal@chuv.ch
Pécoud
Alain
A
Hayoz
Daniel
D
Paccaud
Fred
F
Mooser
Vincent
V
Waeber
Gérard
G
Vollenweider
Peter
P
D000273:Adipose Tissue / Q000033:anatomy & histology* / Q000378:metabolism; D000328:Adult; D000367:Age Factors; D000368:Aged; D000375:Aging / Q000502:physiology*; D001823:Body Composition / Q000502:physiology*; D015992:Body Mass Index; D001835:Body Weight / Q000502:physiology*; D003430:Cross-Sectional Studies; D017097:Electric Impedance; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000453:epidemiology*; D015995:Prevalence; D012016:Reference Values; D012737:Sex Factors; D013557:Switzerland