Abstract
This study explored the Horne Ôstberg Morningness Eveningness Questionnaire
(HO MEQ; Horne and Ôstberg, 1976) as a useful tool in the measurement of diurnal
preference in those over 60 years of age. The HO MEQ and Usual Sleep Patterns
Questionnaire were completed by 376 respondents over 60, with 127 providing
samples for PER3 VNTR genotyping.
HO MEQ score continued to increase with increasing age, but at a lesser rate, in the
over 60 age group compared with those aged 18-59 years. This data was combined
with data from Jones et al. (2007) and Robilliard et al. (2002) to enable comparison
of factor structure across age using multiple group confirmatory factor analysis. The
model derived in the 18-29 age group was of acceptable fit in all age groups except
those over 60 years. The HO MEQ measured similar substantive factors across all
age groups, but factors identified in the over 60 age group used different indicator
questions, the correlation between ‘morning’ and ‘evening’ factors declined with
increasing age, and the ‘morning’ factor accounted for more variance compared with
younger age groups.
The association of the PER3 VNTR polymorphism and HÔ-MEQ score continued in
the over 60 age group, but the frequency of the 4-repeat allele was lower than in
younger age groups. The 4-repeat allele frequency was significantly different
between morning types (M-types) and evening-types (E-types) in the 50+ age
group, but investigation of further age group breakdowns requires a larger sample in
the 50-59 age group.
12 M-types and 11 E-types over 60 years of age were identified by liner regression
of HO MEQ score and age and completed a 14-day light actigraphy/diary study. The
HO MEQ successfully distinguished between early and late sleep schedules. Older
E-types received greater exposure to bright light than older M-types. Significant
differences in the timing of light exposure profiles between M-types and E-types
were a product of differences in sleep-wake timing as previously observed in
younger populations.
This study has shown that the HO MEQ is a useful measure of diurnal preference in
those over 60, but this underlying concept may be measured differently in this age
group. The observed changes in factor structure and early morning light exposure
may contribute to the observed increase in morningness with age.