The Copenhagen Oral Health Senior Study (COHSS) 2004/05, addressed lifestyle factors and oral health in older adults. In total, 1918 of all 6238 subjects, who had participated in the third follow-up of the Copenhagen City Heart Study 2001/03 (detailed published elsewhere [14]), and were still alive, aged ≥65 years old, living in Copenhagen, able to communicate verbally and travel independently, were invited to participate in this oral health study (COHSS), and 783(40%) agreed to participate (Figure 1). Details of participants and non-participants are described elsewhere [15]. Briefly, a larger proportion of non-participants was older and of male gender vs. participants (P <0.001). COHSS was approved by local Ethical Committees (KF 01-144/01).
Dietary assessment
Dietary data were collected using a ‘diet history interview’ based on information about diet in the past month, validated for use in older populations [16]. Participants reported on meal contents and patterns at interview through pre-coded questions. Quantitative information on meals, food intakes and portion sizes was collected using photo-series, cups and measures. All interviews were performed by a single dietician.
Total dietary and supplemental intakesb of vitamin D2 + D3 (μg/d) were estimated. Total vitamin D intakes were within-recommendations (15 μg/d for adults aged 51–70 y; 20 μg/d for ≥71 y) [17] in 4% of subjects and intake was, therefore, classified as < median vs. ≥median (6.8 μg/d).
Total dietary and supplemental calcium intakes were classified as: below vs. within recommendations (1000 and 1200 mg/day for men aged 51–70 and >70 y respectively; 1200 mg/d for women aged ≥ 51 y) [17]. Due to limited information on calcium contents of the supplements used, 800 mg was added to the total amount of calcium intake, but only for those who reported taking calcium supplements daily. Total dairy food intake: <3 vs. ≥3 servings/d, as recommended for elders, by the Food Guide Pyramid [18]. Dairy servings refer to one cup of milk, one slice of cheese or one medium yogurt pot.
Oral examination
One dentist (KH) trained by an experienced clinical examiner (PH-P), performed all oral examinations, including determination of un-stimulated salivary flow rates [19], number of teeth and visible plaque at six sites per tooth, modified from Silness & Löe [20].
Plaque score was determined as % of sites with plaque amongst total sites examined, classified as scoring < median vs. ≥median (9.5%).
Covariates
These included age, gender and primary education (≤7 vs. >7 y), current smoking (yes/no) and intakes of alcohol (above vs. within-recommendations from the Danish National Board of Healtha[21]), sucrose (≤10% vs. >10% of total energy intake, matching suggested thresholds for increased caries rates and lower vitamin and mineral intakes [22]), and daily mineral supplements (yes/no) over the previous year.
From a questionnaire covering 14 common diseases (e.g. cardiovascular, metabolic, respiratory, hepatic, urinary diseases), current ‘medical condition’ was classified as 0–4 vs. ≥5 diseases [15].
Most subjects (98%) reported daily tooth brushing; therefore regular use of dental floss or tooth pick was used for assessing oral hygiene. Elapsed time since last dental-care visit (≤12 vs. >12 months), number of teeth, and salivary flow were included in analyses.
Statistical analysis
Descriptive statistics were presented as ‘mean (±SD)’ or ‘percentage (n)’. Logistic regression was used to assess relationships between calcium and dairy intakes within-recommendations and plaque scores, stratified by vitamin D intakes. Data were analysed with STATA (StataCorp 9.2, TX-USA).