For example, Bar-Oz et al found that the rate of congenital malformations after first-trimester exposure to itraconazole was 4 times higher when ascertained retrospectively rather than prospectively [ 22].
Further research would need to ascertain actual rather than reported nutrition practice.
Another limitation is that we did not directly assess the degree of involution of lobules in the breast, but rather ascertained lobule type from benign biopsy specimens.
As our case subjects were ascertained through offspring rather than affected parents, differential transmission from fathers and mothers as well as reduced risk in the same-sex offspring could theoretically result from the male preponderance among type 1 diabetes cases (32).
Thus, point estimates of risk are somewhat lower in case-ascertained, rather than family-ascertained studies, but because of the large confidence intervals, substantial overlap exists and many differences are not statistically significant.
The desired proof that ( {s}_z^Mto 1 ) as ρ → 0 can be rather easily ascertained by the asymptotic formula that J m → (m !)− 1(α/2) m as |α| → 0 for α ∈ ℂ [2].
Further, depressive and anxiety symptoms were ascertained via self-report rather than standardized clinical interviews which may underestimate the prevalence of these disorders [ 18, 48].
However, it should be noted that these GO annotations were ascertained by sequence homology rather than direct experimentation so should be taken with caution.
Although the number of patients with clinically ascertained CBS deficiency is rather low and the prevalence is only 1 330,000 worldwide [ Mudd et al., 2001], the molecular epidemiological studies suggest an incidence of around 1 10,000 in several European populations [ Gaustadnes et al., 1999; Janosik et al., 2009; Refsum et al., 2004].
In a subsequent study combining data from seven UK cohort studies (Dahm et al, 2010), fibre intake was ascertained by food diaries (rather than the less reliable food frequency questionnaires used in most studies), and issues of confounding (by anthropometric and socioeconomic factors, and dietary intake of folate, alcohol and energy) were addressed.
