alam 4 introduction to key indicators

Anthropometric assessment of adults and elderly

Dr. Dewan S. Alam, MBBS, MMedSc, PhD.Head, Non-communicable Disease Unit

Health System & Infectious Diseases Divisionicddr,b

Why Anthropometric Assessment?

Anthropometry is the measurement of body height, weight & proportions.

It is an essential component of clinical examination of infants, children, pregnant women and adults.

It is used to evaluate both under & over nutrition.

Anthropometric Measuresa. Height (cm) The subject stands erect & bare footed on a stadiometer with a

movable head piece. The head piece is leveled with skull vault & height is recorded

to the nearest 0.5 cm.

b. Weight (kg)

Use a regularly calibrated electronic or balanced-beam scale.

Spring scales are less reliable.

Weigh in light clothes, no shoes

Read to the nearest 100 gm (0.1kg)

BMI measurement and nutritional status

The international standard for assessing body size in adults is the body mass index (BMI).also termed Quetlet’s Index

(Gibson, 2005, p 259)– Formula: BMI = Weight (kg)/ Height (m²)

• Evidence shows that high BMI (obesity level) is associated with type 2 diabetes & high risk of cardiovascular morbidity & mortality.

BMI (WHO – Classification, 2011)

Source: http://apps.who.int/bmi/index.jsp?introPage=intro_3.html

WHO Expert Consultation for Asian

• Proportion of Asian people with a high risk of type 2 diabetes and cardiovascular disease is substantial at BMI's lower than the existing WHO cut-off point for overweight (= 25 kg/m2).

• Cut-off point for observed risk varies from 22 kg/m2 to 25 kg/m2 in different Asian populations and for high risk, it varies from 26 kg/m2 to 31 kg/m2 .

Source: WHO expert consultation, 2004.

Indicators: (contd..)c. % body fat (BIA: Bioelectrical Impedance Analysis)• Widely used method for estimating body composition. • Relatively simple, quick, and noninvasive. • Determines the electrical impedance of body tissues, which provides an

estimate of total body water (TBW). • Using values of TBW derived from BIA, one can then estimate fat-free

mass (FFM) and body fat (adiposity).

(Macias et al., 2007; NIH, 1994)

Indicators: (contd..)• Skinfold thickness measurements provide an estimate of the

size of the subcutaneous fat depot, which in turn, provides an estimate of total body fat.

(Gibson, 2005)

• Skinfold thickness and arm circumference are two measurements that indirectly assess two important components of a body: – Fat and fat-free mass. – Cause, the main storage form of energy and fat-free

mass, usually muscle, is a good indicator of the protein reserves of a body.

Indicators: (contd..)d. Skinfolds:

– Triceps skinfold: Measured at the mid point of the back of the upper arm

– Biceps skinfold: Measured as the thickness of a vertical fold on the front of the upper arm, directly above the center of the cubitalfossa, as the same level as the triceps skinfold.

(Gibson, 2005)

d. Skinfolds: (Contd..)

– Subscapular skinfoldMeasured below and laterally to the angle of the shoulder blade, with the shoulder and arm relaxed. Placing the subjects arm behind the back may assist in identification of the site. The skin fold should angle 45 degree from horizontal, in the same direction as the inner border of the scapula.

– Suprailiac skinfoldMeasured in the mid axillary line immediately superior to the illiac crest. The skinfold is picked up obliquely just posterior to the mid axillary line and parallel to the cleavage lines of the skin.

(Gibson, 2005)

Indicators: (contd..)e. Mid Arm Circumference (MAC) (cm)

f. Waist Circumference (Wst) (cm)Waist circumference is measured at the level of the umbilicus to the nearest 0.5 cm.

g. Hip Circumference (Hip) (cm)– Measured at the point of greatest

circumference around hips & buttocks to the nearest 0.5 cm.

Waist–hip ratio or waist-to-hip ratio(WHR) is the ratio of the circumference of the waist to that of the hips.– Formula= Waist:Hip Ratio = Wst/Hip

Chronic energy deficiency

• To identifying CED affected individuals involves – measuring body weight and height, – then energy intake (or expenditure) and – basal metabolic rate (BMR).

Source: James et al., 1988; Shetty & James, 1994

BMI < 16.0 16.0-16.9 17.0-18.4 > 18.5

CED grade III II I Normal

Over weight & Obesity• The overweight and obesity group defined overweight as -

– Obesity related to a BMI of 25–29.9 kg/m2 (grade 1), – With grade 2 overweight commonly termed as obesity specified for a

BMI of 30–39.9 kg/m2, – Grade 3 or morbid obesity as applying to those with BMI ≥ 40 kg/m2.

(James, 2008)

• Obesity is associated with a rapid increase in health problems such as CVD and diabetes.

(Engelgau et al., 2011)

Weight Gain in Pregnancy - Physiology

• 27.5 lbs (12.5 kg) is “normal” physiologic gain (Hytten 1991)

• 9 kg (~20 lbs) is made up of fetus, placenta, amniotic fluid, uterine/breast hypertrophy, increased blood volume and retained fluid

• 3.5 kg (7.5 lbs) is maternal storage fat

Weight Gain in Pregnancy - Physiology

• 27.5 lbs (12.5 kg) is “normal” physiologic gain (Hytten 1991)

• 9 kg (~20 lbs) is made up of fetus, placenta, amniotic fluid, uterine/breast hypertrophy, increased blood volume and retained fluid

• 3.5 kg (7.5 lbs) is maternal storage fat

Pregnancy Weight Gain Recommendations in the U.S. - History

• 19th century - restriction of food intake to prevent difficult labor

• 1901 - first published study of diet and birth weight – restricted food intake linked to lower BW

• 1920’s – more studies associating weight gain and BW

Pregnancy Weight Gain Recommendations in the U.S. - History

• 1971 – Hytten and Leitch published review of studies from 1950’s and 60’s

• Average gain of 12.5 kg (27.5 lbs) is “physiologic normality” in healthy young primigravid women

• Association between pre-pregnancy weight, weight gain, and birth weight noted in literature

• 1970 – National Academy of Sciences Food and Nutrition Board’s Committee on Maternal Nutrition: 20-25 lbs recommendedAssociated with low weight gain:– Infant mortality– Disability– Mental retardation

Pregnancy Weight Gain Recommendations in the U.S. - History

• 1972 – ACOG also endorsed the 20-25 lb guideline

• 1981 – FNB’s Nutrition Services in PerinatalCare: Inadequate gain = 1kg or less/month in 2nd and 3rd trimesters, Excessive gain = 3kg or more/month

What outcomes have been associated with pregnancy weight gain?

• Birth weight– SGA/IUGR– LGA/macrosomia >>maternal morbidities

• Mode of delivery• Preterm birth• Postpartum weight retention

Weight Gain and Birth Weight

• Well-established relationship, even when using net weight gain (total weight gain minus birth weight of infant)

• Relationship seems to be modified by pre-pregnancy body mass index

• Controversy about relationship between weight gain and birth weight among obese women

The IOM Report and Guidelines

IOM Recommendations for Weight Gain in Pregnancy (1990)

Pre-pregnancy Body Mass Index

IOM Recommended Gestational Weight

Gain (lbs/kg)

<19.8 (Low) 28-40 / 12.5-18

19.8 - 26.0 (Normal) 25-35 / 11.5 - 16

26.1 - 29.0 (High) 15-25 / 7 – 11.5

>29.0 (Obese) At least 15 / At least 6

The IOM Report and Guidelines

• Retrospective, observational data• First widely-accepted guidelines, BMI-

specific• Controversy over guidelines: too high,

too low.• ~ 30 – 40 % of all women• To date: The range for best outcome of

the infant

Weight gain recommendations in Europe & Asia

Austria: Max. 15 kg weight gain Denmark: IOM guidelines Finland: 15 kg for normal weight women Germany: No official guidelines Switzerland: No official guidelines UK: Not weighing during pregnancy Hong Kong: BMI specific weight gain

recommendations No information available: France, Italy, Spain,

Sweden

Weight Gain and Macrosomia

• Strongly associated• Most cases of macrosomia occur in non-diabetic

women• Macrosomia is associated not just with infant

trauma, but with multiple increased risks of maternal morbidity: cesarean birth, severe perineal lacerations, peripartum infection, and prolonged hospital stay (even among those delivering vaginally)

Weight Gain and Cesarean Birth

• High weight gain is associated with increased risk of both prolonged labor and cesarean birth

• This relationship is only partly attributable to higher birth weight

• Even when birth weight controlled for in multivariate analysis, high weight gain is an independent risk factor for cesarean birth

Weight Gain and Preterm Birth

• Multiple epidemiologic studies have associated poor gestational gain with increased risk of preterm birth

• Obvious confounder of length of gestation as well as birth weight – most studies have addressed this

• Most studies have not stratified by pre-pregnancy BMI, some excluded obese women

Weight Gain and Preterm Birth Study -Results

• Low BMI group gaining below guidelines had PTB rate of 5.9% vs. 3.5% for those gaining within guidelines (P< 0.001)

• High BMI group gaining below guidelines had PTB rate of 8.1% vs. 3.8% for those gaining within guidelines (P<0.001).

• Normal BMI group gaining below guidelines had PTB rate of 5.2% vs. 3.4% for those gaining within guidelines (P<0.001).

Gestational Weight Gain – Methodologic Challenges

• What measure of weight gain to use?

• How reliable are self-reported weights?

• Gestational age assessment

• Race/ethnicity variation

• Limitation of retrospective/epidemiologic data

• Optimal weight gain depends on the outcome one studies

What can we do? Do interventions work?

• Historically: guidelines/provider advice can impact actual weight gain

• Few studies have linked interventions to outcomes beyond #kg gained

Interventions

• By-mail patient education• Regular clinical meetings for education with

goal-setting• Phone calls between visits• Newsletters• Personal graph of weight gain

Goals for Future Research

• Achieve adequate weight gain in pregnancy• Studies in overweight/obese women• Qualitative research – patient and provider

attitudes, beliefs• RCTs of novel interventions – both weight gain

and other outcomes – low glycemic load diet trial – Janet King PI

Why is weight gain important during pregnancy?

• The extra weight during pregnancy provides – Nourishment to developing baby– Stored for breastfeeding baby after delivery

Picture Source: (WHO, 2011; p 17)

New Recommendations for Total and Rate of Weight Gain During Pregnancy, by Prepregnancy BMI

Developed by WHO and adopted by NHLBI. Source: Rasmussen, & Yaktine, 2009; Rasmussen et al., 2009.

The guidelines and supporting recom-mendations are intended to be used in concert with good clinical judgment and should include a discussion between the woman and her care provider about diet and exercise.

Data availability on Information and Accountability for Woman’s and Children’s Health

WHO, (2011). Monitoring maternal, newborn and child health: understanding key progress indicators. p 15.

Strengthening countries’ capacity to monitor and evaluate results

• High quality data are critically needed in order to enable global assessment of progress on the Commission’s recommended measures of coverage, impact, financing, and equity related to women’s and children’s health.

• The availability of accurate, timely, and consistent data at the national and sub-national levels is crucial for countries to be able to effectively manage their health systems, allocate resources according to need, and ensure accountability for delivering on health commitments.

(WHO, 2011, p 13)

ADVANTAGES OF ANTHROPOMETRY

• Objective with high specificity & sensitivity• Measures many variables of nutritional significance (Ht, Wt,

MAC, HC, skin fold thickness, waist & hip ratio & BMI).• Readings are numerical & gradable on standard growth

charts.• Readings are reproducible. • Non-expensive & need minimal training

Limitations of Anthropometry

• Inter-observers errors in measurement

• Limited nutritional diagnosis

• Problems with reference standards, i.e. local versus international standards.

• Arbitrary statistical cut-off levels for what considered as abnormal values.