Friday, January 4, 2019

For longevity, is it better to be short or tall?

Being short is associated with worse outcomes for critically ill adults.

A large retrospective study of 233,000 men and 184,000 women consecutively admitted to 210 ICUs in the UK over a six-year period found hospital and ICU mortality decreased with increasing height after adjusting for available potential confounders. The difference was statistically significant.

The definition of short or tall was based on the median height of the subjects—175 cm (5’9”) for men and 162 cm (5’2”) for women. These figures are nearly the same as the averages for non-hospitalized adults.

The study had several limitations. Height was measured in just 44.5% of the group while the rest were based on estimates. However, the authors noted the median estimated height was exactly the same as the measured height for men and only 1 cm different for women, and measuring height in critically ill patients is difficult.

The results may not be accurate because of undocumented confounders such as functional status, childhood exposures to radiation or chemotherapy, dosing of medications, size of endotracheal tubes, and tidal volumes in patients on ventilators. The impact of frailty, aging, and disease was also unknown.

Like all retrospective studies, association does not necessarily mean causation. To their credit, the authors concluded that height may be a risk factor for short-term mortality in critically ill patients.

Another recent paper suggests being tall increases cancer risk. Math trigger warning! The paper contains several passages like this:
In 18 of 23 different types of tumors looked at, being tall increased the risk of cancer by about 10% in both men and women. And the risk increased by 10% for every 10 cm increaser in height. This effect is primarily due to tall people having an increase in the total number of cells in their bodies.

Obesity, in which the cells are larger but not more numerous, does not have the same effect as height on cancer risk.

Height did not increase cancer risk in a five types of tumors—pancreas, esophagus, stomach, mouth/pharynx, and cervix. This may be due to the association of these cancers with external factors like infection and carcinogens.

Since I am of average height and, like all of us, getting shorter with age, I’m not sure what to do with the information. Should I buy shoes with thicker soles or let nature take its course?

2 comments:

Robert Ley said...

Paragraph 2: 162cm is about 5'4"

Skeptical Scalpel said...

Robset,

Thank you for pointing out the error. I have corrected it.

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