LASA161 (grip strength is described here)
LASA171 (data processing of calf measurement; from wave I onwards processed in LASA161)
LASAC185 (data processing of Ankle, Knee and Pulse width, not described yet)
Contact: Marjolein Visser
Measurement instruments in LASA
The anthropometric measures obtained during the medical interview at each LASA examination are listed in the table below (Availability of information per wave)..
Height is measured to the nearest 0.001 m using a stadiometer. Height in old age is not a good indicator of maximum adult height. Due to scoliosis and kyphosis height may decrease. This decrease in height is sometimes used as a predictor of vertebral fracture(s).
In the LASA study, no accurate measurement could be obtained for some participants due to one of the following reasons: not able to stand, hairdo, head not parallel, shoes, refused, kyphosis or scoliosis. These particularities are listed as separate variables. Depending on the research question height measurements with reported particularities should be set to missing. In case no accurate measurement was obtained you can rely on the self-reported height (asked at each medical interview).
In contrast to total body height, the length of the long bones is not influenced by aging. Knee height is older people is sometimes used as an indicator of maximum adult height or actual height.(1) Knee height can be used as a substitute of body height in analyses or knee can be used to predict maximum adult height using published prediction equations. Knee height is measured at the LASA B examination only at the left leg. Particularities during the measurement are listed as a separate variable and include: refused, trousers or right leg. See also: Recoding height and weight.
Weight is measured to the nearest 0.1 kg using a calibrated bathroom scale (Seca, model 100, Lameris, Utrecht, The Netherlands). Weight is a simple indicator of nutritional status. Particularities during the measurement are listed in a separate variable and include: cannot stand, clothes, corset, brace, prosthesis, amputation, weight > 150 (maximum of scale) or refused. In the ideal situation weight should be measured with the participants wearing underclothing only. In previous LASA papers the following corrections have been made to adjust the measured body weight for clothing (minus 2 kg) or a corset (minus 1 kg).(2) In all medical interviews a self-reported weight has been obtained which can be used in case no measured weight is available.
Since taller persons weigh more, a better indicator of nutritional status is the body mass index (BMI). BMI can be calculated by dividing body weight (in kg) by height (in m) squared and its unit is kg/m2. According to the 1998 guidelines(3) , persons can be categorized according to their BMI:
- Underweight < 18.5 kg/m2
- Normal weight 18.5 - 24.9
- Overweight 25.0 - 29.9
- Obesity class I 30.0 - 34.9
- II 35.0 - 39.9
- III 40.0 +
Skinfolds are measured to the nearest 0.2 cm at precisely defined locations of the body using a skinfold caliper (Holtain Tanner/Whitehouse skinfold caliper, Holtain Ltd., Crosswell, UK). The skinfold represents the thickness of the subcutaneous fat layer (=fat right under the skin) in mm. Since the thickness of the layer of subcutaneous fat differes at different locations of the body, usually several skinfolds are being measured to get a representative value.
In LASA, all skinfolds were measured in triplicate on the left side of the body. The following locations were used to measure the skinfolds.(4) Triceps: in the midline of the posterior aspect of the arm, over the triceps muscle, at a point midway between the lateral projection of the acromion process of the scapula and the inferior margin of the olecranon process of the ulna. Biceps: the thickness of a vertical fold raised on the anterior aspect of the arm, over the belly of the biceps muscle, at the same midpoint of the arm defined for the triceps skinfold. Suprailiac: is measured in the midaxillary line immediately superior to the iliacrest. Subscapular: the skinfold is picked up on a diagonal, inclined infero-laterally approximately 45 degrees to the horizontal plane in the natural cleavage lines of the skin. The site is just inferior to the inferior angle of the scapula. Listed particularities include: no bare arm, oedema, skinfold > 40 mm (40 mm is maximum of caliper), tight skin, refused.
For each skinfold the mean of the replicate measurements (usually 3) should be used in the analyses. This absolute value (in mm) can be used as an indicator of body fat. Very often the sum of 2 skinfolds (triceps plus biceps) or the sum of 4 skinfolds (triceps plus biceps + suprailiaca + subscapula) is used. Another approach is to calculate total body fat by using a prediction equation based on 1, 2 or 4 skinfolds. An example of these prediction equations can be found in references 5 and 6.(5-6)
Waist and hip circumference
The waist circumference and the waist/hip circumference ratio (WHR = waist circumference divided by hip circumference) are frequently used as an indicator of body fat distribution.(7) Both a large waist circumference and a large WHR are indicative of an accumulation of fat in the trunk (=abdominal fat distribution) and a large amount of visceral fat (= fat stored around and in between organs). Visceral fat is thought to be more harmful to health than subcutaneous fat stores (= fat stored under the skin). In epidemiological studies a large waist and a high WHR are predictive of cardiovascular disease and diabetes mellitus. Both the waist and the WHR increase with age due to body fat accumulation in the abdomen with aging.
The waist circumference is measured to the nearest 0.001 m midway between the lower rib margin and the iliacrest following a normal expiration. The hip circumference is measured to the nearest 0.001 m at the level of the widest circumference over the greater trochanter. Listed particularities include: lying down, difficult to find right location, many skinfolds, other, refused. Single measurements of the waist and hip were obtained at LASA B and LASA D. Duplicate measurements were obtained at all other LASA cycles. Statistical analyses using the difference in circumferences between examinations are not influenced by the fact that no equal number of measurements was obtained at each examination. In this case, the single measurement at LASA B can be compared with the mean of the duplicate measures at LASA C. However, for other statistical procedures (e.q. analyses of variance) this might be a problem, and the first measurement only should be used.
The arm circumference is a simple measure of nutritional status. The circumference is measured in duplicate to the nearest 0.001 m at a point midway between the lateral projection of the acromion process of the scapula and the inferior margin of the olecranon process of the ulna.4 The mean of the two measurements should be used in the analyses. Listed particularities include: no bare arm, respondent is sitting down, right arm, space between tape and arm, refused.
The arm circumference is often used in combination with triceps (and biceps) skinfold measurements to calculate the arm muscle cross-sectional area, a crude measure of muscle mass. The following formulas can be used to calculate arm cross-sectional muscle area:
Total arm area = (arm circumference squared) / 12.566371
Arm radius = (arm circumference / 6.2831853) - (triceps / 2)
Arm cross-sectional muscle area = (arm radius squared) * 3.1415927
If LASA examination contains both triceps and biceps skinfold, use the mean of these two skinfolds to represent the fat layer under the skin instead of the triceps skinfold only.
The calf circumference is a simple anthropometric measure that is highly correlated with muscle mass. The layer of subcutaneous fat is generally thin at the calf and, in contrast to the arm, no correction for this fat layer is made. The calf circumference is measured to the nearest 0.001 m on the left leg with the participant standing straight, feet 20 cm apart, body weight equally distributed on both feet and at the level of the widest circumference of the calf. Particularities during the measurement are listed and include: refused, respondent is sitting down, not physically able, right calf, impedents, edema present, support stocking, long underwear, space between tape and calf, other. In the LASA B examination, a single measurement of the calf circumference was measured in half the cohort only (n=1390) and the variable can be found in file LASAB171. In the LASA D examination the calf circumference was measured in duplicate. Statistical analyses using the difference in circumferences between examinations are not influenced by the fact that no equal number of measurements was obtained at each examination. However, for other statistical procedures (e.q. analyses of variance) this might be a problem.
LASAB161 / LASAC161 / LASAD161 / LASAE161 / LAS2B161 / LASAF161 / LASAG161 / LASAH161 / LASA3B161 / LASMB161 / LASAI161 (medical interview, in Dutch)
LASAB161 / LASAC161 / LASAD161 / LASAE161 / LAS2B161 / LASAF161 / LASAG161 / LASAH161 / LAS3B161 / LASMB161 (LASMB161 not processed yet) / LASAI161
Calf measurement: LASAB171 / LASAD171 / LASAE171 / LAS2B171 / LASAF171 / LASAG171 / LASAH171 / LAS3B171 (from wave I onwards, calf measurement was processed in LASAI161)
Ankle, Knee and Pulse width: as part of LASAC185
Availability of information per wave 1
|Grip strength 2||Me||Me||Me||Me||Me||Me||Me||Me||Me||Me|
|Ankle, Knee and Pulse width||Me|
1 More information about the LASA data collection waves is available here.
* 2B=baseline second cohort;
3B=baseline third cohort;
MB=migrants: baseline first cohort (Under Construction)
Me=data collected in medical interview
2 Grip strength is described elsewhere
- Chumlea WC, Roche AF, Steinbaum ML. Estimating stature from knee height for persons 60 to 90 years of age. J Am Geriatr Soc 1985;33:116-120.
- Visser M, Launer LJ, Deurenberg P, Deeg DJH. Total and sports activity in older men and women: relation with body fat distribution. Am J Epidemiol 1997;145:752-61.
- Clinical guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults. Bethesda, MD: National Institutes of Health; 1998. Available at: http://www.nhlbi.nih.gov/guidelines.
- Anthropometric standardization reference manual. Eds: Lohman TG, Roche AF, Martorall R. Human Kinetics Books, Champaign IL, 1988.
- Durnin JVGA, Womersley J. Body fat assessed from total body density and its estimation from skinfold thickness: measurements on 481 men and women aged from 16 to 72 years. Br J Nutr 1974;32:77-97.
- Visser M, Van den Heuvel E, Deurenberg P. Prediction equation for the estimation of body composition in the elderly using anthropometric data. Br J Nutr 1994;71:823-33.
- Van der Kooy K, Seidell JC. Techniques for the measurement of visceral fat: a practical guide. Int J Obes Relat Metab Disord 1993;17:187-196.
Recoding height and weight
Syntax Anthropometry B-F (pdf)