Few things I noticed:
The percentages skew towards the obese:
Of the 11 247 participants examined in the 1999–2000 AusDiab study, data were available in the 2004–2005 follow-up survey for 6140 (54.1% female; mean age, 56.5 years). Based on BMI, 31.6% were normal weight, 41.3% were overweight and 27.0% were obese. The proportions with normal WC, abdominal overweight and abdominal obesity were 32.8%, 26.3%, and 41.0%. When combined definitions (based on BMI and/or WC) were used, 24.7% were normal, 32.4% were overweight and 42.9% were obese.
The 2007–2008 NHS reported similar BMI-based rates for adults aged ≥ 25 years: normal, 34.1%; overweight, 39.1%; and obese, 26.9%.
This seems to be because they included WC obesity, not really something I’ve seen done much so far in these epidemiological studies. It would suggest there are many more ‘obese’ people than the BMI suggests.
Note: no controls for weight-based interventions. That is, costs associated with bariatric surgery (to include these would seem like the dog biting its own tail, as it were). Also, no controls for when fatness is a symptom of a condition in an obvious way, like a side-effect of certain prescription medications or a symptom of PCOS or hypoglycemia. This studies skews fatness as ’cause’ of greater medical costs, when fatness can be a symptom of conditions which would naturally push costs up.
In that same breath, diseases with a symptom of wasting (like some cancers) should be controlled for.
The mean annual payment from government subsidies was $3600 (95% CI, $3446–$3753) per person (Box 1). Based on BMI, government subsidies per person increased from $2948 (95% CI, $2696–$3199) for people of normal weight to $3737 (95% CI, $3496–$3978) for the overweight and $4153 (95% CI, $3840–$4466) for the obese. A similar trend was observed for WC-based weight classification.
This isn’t saying anything new. We’ve known for a while (need a link here) that poorer people in our modern society tend to be fatter than richer people. Poorer people consume more government subsidies. Hence fatter people consume more government subsidies.
I think that this study could have been much more rigorous if they would have done a few things:
- Controlled for obesity-related interventions like bariatric surgery and weight-loss interventions
- Controlled for costs associated to conditions and medications that clearly have increased (or decreased) weight as a side effect, as that would skew the data
- Controlled for income when calculating government subsidies per person
Then again, if those things were done, then I don’t think we’d see such a neat, eye-popping linear relationship between ‘obesity’ and costs, would you?
This ‘study’ is prop for some future political theatrics, nothing more.