Increasing body size among adult cook islanders between 1966 and 1996

There is limited evidence of a secular trend toward increased body size among populations in the Pacific Region, although some populations have shown a clear rise in overweight and obesity across the past 30 years or so. Mean height, weight and body mass index (BMI) of adults surveyed in 1996 on Rarotonga, the Cook Islands, are reported by age group and compared with data collected in 1966 by Evans and Prior, to determine the extent to which a secular trend in increasing body size has taken place across this 30-year period. In addition, a comparison of these anthropometric variables between subjects born on the most modernized island of Rarotonga with those born on other less-modernized islands is made, to determine the extent to which adult body size differs according to place of origin. Comparing the sample of those born on Rarotonga, the most modernized island, with those born on other, less modernized islands shows those born on Rarotonga to be taller, but not relatively heavier than those born elsewhere in the Cook Islands. Both males and females of the 1996 sample of adults are significantly taller, heavier, with higher BMI compared with the 1966 sample, indicating a secular trend toward increased body size across this 30-year period. The mean BMIs of the younger age groups in 1996 are greater than those of the same age groups in 1966, indicating a secular trend toward greater body fatness. There has been a significant increase in obesity among both males and females. In 1966, 14% of males had a BMI greater than 30, while in 1996, the proportion was 52%. Among females, 44% of those measured in 1966 had a BMI greater than 30, while in 1996 the proportion was 57%. The higher mean stature of younger adult males relative to older ones suggests that the secular trend toward increasing height may have been underway prior to 1966. The mean statures and weights of adults aged 60 years and older in the 1996 sample are more similar to values given for most age groups in the 1966 sample, indicating that the secular trend toward increased weight and height may have begun 50-60 years ago.