Strengths and limitations
The main strength of this study is the availability of a very large set
of validated FFQ data. (21) Furthermore, to our knowledge, this study is
the first to develop a nutrient specific screening tool with a minimal
number of predictors that is applicable on an individual level while
maintaining predictive accuracy. Finally, as this tool was developed in
line with clinical needs, it is an evidence-based tool that should be
relatively easy to implement in practice.
A limitation of this study is the use of dietary surveys, which could be
prone to bias (22). Dietary surveys are primarily subject to
underreporting (23, 24). We minimalized the effects of underreporting by
eliminating FFQs with unrealistically low dietary intakes. Additionally,
the Predict study is a tertiary hospital based cohort, and disease or
medication related side effects can influence dietary habits, and with
that calcium intake or uptake. Since calcium is absorbed in the small
intestine, certain gastrointestinal (inflammatory) diseases or
intestinal surgery can severely restrict calcium uptake. (25) However,
the tool assesses dietary calcium intake, rather than uptake. Intake
levels are unlikely to be affected by a reduced uptake. Therefore, there
is no reason to suspect that this would influence the tool’s
generalizability. We cannot think of any other indication for tertiary
pregnancy care where calcium intake would be severely compromised, and
therefore, we think our results apply to each pregnant woman,
irrespective of underlying comorbidities or risks.