Why do boys aged 4 to 8 use more nutritional supplements than girls in this Canada fact sheet?

In this survey there is an anomalty that only boys aged 4 to 8 use more nutritional supplements than girls of the same age in Canada.

Can someone please explain or interpret this oddity? It is never explained in the source.

I guess boys aged 4 to 8 grow not as tall or big as girls at the same age, then the worried moms feed more supplments to their boys. Or perhaps there is some bias in data collection?

• Is the difference statistically significant? From the limited data you presented it doesn't look to be. – Carey Gregory Apr 29 '19 at 3:44
• I think this is a problem, I didn't find any numbers regarding sample size or statistical significance. So this oberservation may not be trusted? – J. Doe Apr 29 '19 at 5:04
• I don't think any conclusions can be drawn from it. The article is very thin on information. – Carey Gregory Apr 29 '19 at 14:00
• @J.Doe It's not that the observation shouldn't be trusted, it's that you need to apply some understanding of statistics to interpreting the data. If you flipped a coin 20 times and it came up 'heads' 12 times, you wouldn't have sufficient evidence to state that it's an unfair coin even though 12 is different from the expected value of 10. Because each coin flip is a random event, you expect that even if the coin is fair, 12 heads is a fairly common outcome. The same logic applies to other measuresments like these. – Bryan Krause Apr 29 '19 at 14:28

In age groups 4-8 and 9-13, supplements use is almost the same in boys and girls. At these ages, there are much fewer health conditions or concerns that would be related to a person's sex, than at older ages.

Menstruating, lactating and pregnant women use more iron supplements than men of same age (ods.od.nih.gov):

Approximately 14% to 18% of Americans use a supplement containing iron. Rates of use of supplements containing iron vary by age and gender, ranging from 6% of children aged 12 to 19 years to 60% of women who are lactating and 72% of pregnant women.

Many pregnant women also use "prenatal vitamins" (PubMed, 2014):

56% of black and 86% of white women reported pre- and/or post-conceptional PNV use.

Postmenopausal women use more calcium supplements to prevent or treat osteoporosis, which is much more common in women than in men (ods.od.nih.gov).

A 2014 survey in the US also showed that more women use nutritional supplements than men.

• Thanks! this is very informative regarding the health question (: – J. Doe May 28 '19 at 22:07