Body size (50+ years)

A healthy body size is recognised as being important for good health and wellbeing, with evidence showing that obese children and adults are at greater risk of short- and long-term health consequences (Ministry of Health 2008).

Body mass index (BMI) provides a useful population-level indicator of excess body weight. It is a measure of weight adjusted for height, and is calculated by dividing weight in kilograms by the square of height in metres (kg/m2). BMI is used internationally to classify underweight, overweight and obese.

It should be noted that the BMI provides a crude measure and does not distinguish between weight associated with muscle and weight associated with fat. However, it does provide a good estimate of increased risk of health conditions associated with obesity (World Health Organization 2008).

To comply with current international practice, the same BMI cut-off points are used for all ethnic groups (please refer to the 2006/07 New Zealand Health Survey body size technical report for more information). Therefore, data presented in this publication should not be compared with those presented in the first edition of Tatau Kahukura: Māori Health Chart Book, which used ethnic-specific cut-off points to analyse body size (Ministry of Health 2006).

Table 11: International BMI cut-off points for adults aged 18 years and over
Classification BMI score kg/m2 Risk of health conditions
Underweight < 18.50 Low risk
Overweight 25.00-29.99 Increased risk
Obese > 30.0 Substantially increased risk

Source: Ministry of Health 2008

Note: This table only includes health conditions associated with increasing BMI.

Table 12 shows that older Māori of both genders and age groups are significantly more likely than non-Māori of the same gender and age to be overweight or obese. However, the table also shows that both Māori males and females are less likely to be overweight (although the difference is not statistically significant), whereas they are significantly more likely to be obese compared with non-Māori of the same age and gender.

Māori males aged 65+ years are twice as likely as non-Māori males of the same age to be obese (RR 2.22, CI 1.62–2.82). Māori females in this age group are more than 1.5 times more likely than non-Māori to be obese (RR 1.73, CI 1.34–2.12).

How to interpret results – tables

Table 12: Body size indicators, Māori and non-Māori, by gender, 2006/07
  Males Females
  50–64 years 65+ years 50–64 years 65+ years
Indicator Māori non-Maori Māori non-Māori Māori non-Māori Māori non-Māori
Underweight, 2006/07, percent 0.3
(0.1–1.0)
0.8
(0.2–1.9)
0.4
(0.0–1.5)
0.7
(0.3–1.5)
6.9
(2.1–15.7)
0.9
(0.5–1.6)
Overweight, 2006/07, percent 32.7
(24.2–41.1)
44.1
(40.4–47.8)
36.1
(24.6–47.6)
50.9
(46.5–55.3)
25.6
(19.2–32.0)
35.7
(31.9–39.5)
30.6
(21.2–40.1)
38.1
(35.1–41.0)
Obese, 2006/07, percent 61.7
(52.5–70.8)
32.9
(29.6–36.3)
55.5
(42.4–68.6)
25.0
(21.7–28.3)
57.4
(50.0–64.8)
31.9
(28.4–35.4)
48.9
(39.1–58.8)
28.3
(25.3–31.3)
Overweight or obese, 2006/07, percent 94.3
(90.8–97.9)
77.0
(73.9–80.2)
91.6
(84.7–98.5)
75.9
(72.4–79.3)
83.0
(77.7–88.4)
67.6
(64.5–70.7)
79.6
(71.5–87.7)
66.3
(63.3–69.4)

Source: 2006/07 New Zealand Health Survey, Ministry of Health

Notes:
Age standardised to the 2001 Census total Māori population.
Prioritised ethnicity has been used – see Ngā Tapuae me ngā Raraunga: Methods and data sources for further information.
A dash (–) indicates that data were unavailable due to low counts.

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